diff --git a/src/Comms/CMakeLists.txt b/src/Comms/CMakeLists.txt
index c118d6313608..543b7399b6fc 100644
--- a/src/Comms/CMakeLists.txt
+++ b/src/Comms/CMakeLists.txt
@@ -68,6 +68,35 @@ endif()
 # ----------------------------------------------------------------------------
 add_subdirectory(Bluetooth)
 
+# ----------------------------------------------------------------------------
+# ZeroConf/mDNS Service Discovery
+# ----------------------------------------------------------------------------
+if(QGC_ZEROCONF_ENABLED)
+    if(NOT USE_SYSTEM_QMDNSENGINE)
+    CPMAddPackage(
+        NAME qmdnsengine
+        GITHUB_REPOSITORY nitroshare/qmdnsengine
+        GIT_TAG master
+        OPTIONS
+            "BUILD_DOC OFF"
+            "BUILD_EXAMPLES OFF"
+            "BUILD_TESTS OFF"
+    )
+
+    if(TARGET qmdnsengine)
+        qgc_disable_dependency_warnings(qmdnsengine)
+        target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE qmdnsengine)
+        target_compile_definitions(${CMAKE_PROJECT_NAME} PRIVATE QGC_ZEROCONF_ENABLED)
+    else()
+        message(WARNING "QGC: qmdnsengine target not created, ZeroConf will be disabled")
+    endif()
+    else()
+    find_package(qmdnsengine REQUIRED)
+    target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE qmdnsengine)
+    target_compile_definitions(${CMAKE_PROJECT_NAME} PRIVATE QGC_ZEROCONF_ENABLED)
+    endif()
+endif()
+
 # ============================================================================
 # Communication Link Subdirectories
 # ============================================================================
diff --git a/src/FirmwarePlugin/APM/CMakeLists.txt b/src/FirmwarePlugin/APM/CMakeLists.txt
index 57d9e79903f1..af3ab1487988 100644
--- a/src/FirmwarePlugin/APM/CMakeLists.txt
+++ b/src/FirmwarePlugin/APM/CMakeLists.txt
@@ -47,12 +47,17 @@ qt_add_resources(${CMAKE_PROJECT_NAME} firmaware_plugin_apm_resource
 
 #===========================================================================#
 
+if(NOT USE_SYSTEM_PARAMETERS)
 CPMAddPackage(
     NAME ArduPilotParams
     GITHUB_REPOSITORY ArduPilot/ParameterRepository
     GIT_TAG 037ff6bcfc080608544a4526f2c22406f2cce60f
 )
 
+else()
+    set(ArduPilotParams_SOURCE_DIR /usr/share/ParameterRepository)
+endif()
+
 # Dynamically discover all parameter definition files.
 # Directory layout: {Vehicle}-{Major}.{Minor}/apm.pdef.json
 # Resource alias:   FirmwarePlugin/APM/APMParameterFactMetaData.{Vehicle}.{Major}.{Minor}.json
diff --git a/src/GPS/CMakeLists.txt b/src/GPS/CMakeLists.txt
index 902a62e6e255..331ebf858eeb 100644
--- a/src/GPS/CMakeLists.txt
+++ b/src/GPS/CMakeLists.txt
@@ -38,12 +38,16 @@ add_subdirectory(NTRIP)
 # PX4 GPS Drivers Integration
 # ============================================================================
 
+if(NOT USE_SYSTEM_PX4-GPSDRIVERS)
 CPMAddPackage(
     NAME px4-gpsdrivers
     GITHUB_REPOSITORY PX4/PX4-GPSDrivers
     GIT_TAG caf5158061bd10e79c9f042abb62c86bc6f3e7a7
     SOURCE_SUBDIR src
 )
+else()
+set(px4-gpsdrivers_SOURCE_DIR /usr/src/PX4-GPSDrivers)
+endif()
 
 # NOTE: Using file(GLOB) for external dependency sources
 # CONFIGURE_DEPENDS ensures CMake re-runs if files are added/removed
diff --git a/src/MAVLink/CMakeLists.txt b/src/MAVLink/CMakeLists.txt
index 43a18b671b14..ae88ab727819 100644
--- a/src/MAVLink/CMakeLists.txt
+++ b/src/MAVLink/CMakeLists.txt
@@ -34,6 +34,7 @@ target_include_directories(${CMAKE_PROJECT_NAME} PRIVATE ${CMAKE_CURRENT_SOURCE_
 
 message(STATUS "QGC: Building MAVLink")
 
+if(NOT USE_SYSTEM_MAVLINK)
 CPMAddPackage(
     NAME mavlink
     GIT_REPOSITORY ${QGC_MAVLINK_GIT_REPO}
@@ -43,6 +44,22 @@ CPMAddPackage(
         "MAVLINK_VERSION ${QGC_MAVLINK_VERSION}"
 )
 
+else()
+set(mavlink_SOURCE_DIR /usr/include/c_library_v2)
+file(GLOB MAVLINK_SOURCES1 ${mavlink_SOURCE_DIR}/*)
+file(GLOB MAVLINK_SOURCES2 ${mavlink_SOURCE_DIR}/all/*)
+file(GLOB MAVLINK_SOURCES3 ${mavlink_SOURCE_DIR}/common/*)
+file(GLOB MAVLINK_SOURCES4 ${mavlink_SOURCE_DIR}/development/*)
+
+target_sources(${CMAKE_PROJECT_NAME}
+    PRIVATE
+        ${MAVLINK_SOURCES1}
+        ${MAVLINK_SOURCES2}
+        ${MAVLINK_SOURCES3}
+        ${MAVLINK_SOURCES4}
+)
+endif()
+
 if(mavlink_ADDED)
     add_dependencies(${CMAKE_PROJECT_NAME} mavlink)
     target_include_directories(${CMAKE_PROJECT_NAME}
diff --git a/src/MAVLink/LibEvents/CMakeLists.txt b/src/MAVLink/LibEvents/CMakeLists.txt
index 3dedd962c435..adf23f85ff0f 100644
--- a/src/MAVLink/LibEvents/CMakeLists.txt
+++ b/src/MAVLink/LibEvents/CMakeLists.txt
@@ -18,6 +18,7 @@ target_include_directories(${CMAKE_PROJECT_NAME} PRIVATE ${CMAKE_CURRENT_SOURCE_
 # LibEvents Library Integration
 # ============================================================================
 
+if(NOT USE_SYSTEM_LIBEVENTS)
 CPMAddPackage(
     NAME libevents
     GITHUB_REPOSITORY mavlink/libevents
@@ -30,3 +31,29 @@ CPMAddPackage(
 # warnings when its headers are compiled as part of QGC source code.
 target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE libevents)
 target_include_directories(${CMAKE_PROJECT_NAME} SYSTEM PRIVATE ${libevents_SOURCE_DIR}/libs/cpp)
+
+else()
+find_package(libevents REQUIRED)
+set(LIBEVENTS_INCLUDE_DIRS /usr/include/libevents)
+target_include_directories(${CMAKE_PROJECT_NAME} PRIVATE ${LIBEVENTS_INCLUDE_DIRS})
+find_library(EVENTS_HEALTH_LIB events_health_and_arming_checks)
+find_library(EVENTS_PARSER_LIB events_parser)
+target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE ${EVENTS_HEALTH_LIB})
+target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE ${EVENTS_PARSER_LIB})
+find_package(PkgConfig)
+
+if(TARGET libevents)
+    if(TARGET events_health_and_arming_checks)
+        if(TARGET events_parser)
+            target_link_libraries(events_health_and_arming_checks PRIVATE events_parser)
+            message(STATUS "Fixed: events_health_and_arming_checks -> events_parser")
+        endif()
+    endif()
+
+    if(TARGET events::health_and_arming_checks AND TARGET events::parser)
+        target_link_libraries(events::health_and_arming_checks PRIVATE events::parser)
+        message(STATUS "Fixed: events::health_and_arming_checks -> events::parser")
+    endif()
+endif()
+endif()
+
diff --git a/src/Utilities/Compression/CMakeLists.txt b/src/Utilities/Compression/CMakeLists.txt
index 262d39060b88..d40c8a23fc9f 100644
--- a/src/Utilities/Compression/CMakeLists.txt
+++ b/src/Utilities/Compression/CMakeLists.txt
@@ -43,6 +43,7 @@ if(WIN32)
     )
 endif()
 
+if(NOT USE_SYSTEM_ZLIB)
 CPMAddPackage(
     NAME zlib
     GITHUB_REPOSITORY madler/zlib
@@ -73,10 +74,15 @@ if(NOT TARGET ZLIB::ZLIB)
     add_library(ZLIB::ZLIB ALIAS zlibstatic)
 endif()
 
+else()
+target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE z)
+endif()
+
 # ============================================================================
 # XZ (LZMA) Integration - liblzma from xz-utils
 # ============================================================================
 
+if(NOT USE_SYSTEM_XZ-EMBEDDED)
 CPMAddPackage(
     NAME xz
     VERSION 5.8.2
@@ -127,10 +133,36 @@ else()
     message(FATAL_ERROR "liblzma target not found")
 endif()
 
+else()
+
+add_library(xz STATIC ${LIB_PREFIX}/libxz.a)
+set_target_properties(xz PROPERTIES
+    IMPORTED_LOCATION "${LIB_PREFIX}/libxz.a"
+    INTERFACE_INCLUDE_DIRECTORIES "/usr/include/xz-embedded"
+)
+
+target_compile_definitions(xz
+    PUBLIC
+        XZ_USE_CRC64
+        XZ_USE_CRC32
+        XZ_DEC_ANY_CHECK
+)
+
+target_include_directories(xz INTERFACE /usr/include/xz-embedded)
+target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE xz)
+target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE "${LIB_PREFIX}/libxz.a")
+endif()
+
 # ============================================================================
 # Zstandard (ZSTD) Integration
 # ============================================================================
 
+# Suppress CMake warning about MSVC not being an ASM assembler (CMP0194)
+if(POLICY CMP0194)
+    set(CMAKE_POLICY_DEFAULT_CMP0194 NEW CACHE STRING "" FORCE)
+endif()
+
+if(NOT USE_SYSTEM_ZSTD)
 CPMAddPackage(
     NAME zstd
     VERSION 1.5.7
@@ -174,12 +206,16 @@ if(TARGET libzstd_static)
 else()
     message(FATAL_ERROR "libzstd_static target not found")
 endif()
+else()
+    target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE zstd)
+endif()
 
 # ============================================================================
 # LZ4 Integration (Fast compression) - Optional
 # ============================================================================
 
 if(QGC_ENABLE_LZ4)
+    if(NOT USE_SYSTEM_LZ4)
     CPMAddPackage(
         NAME lz4
         VERSION 1.10.0
@@ -207,6 +243,9 @@ if(QGC_ENABLE_LZ4)
     else()
         message(FATAL_ERROR "lz4_static target not found")
     endif()
+    else()
+        target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE lz4)
+    endif()
 endif()
 
 # ============================================================================
@@ -219,6 +258,7 @@ endif()
 # - TODO: Update to tagged release when bzip2 publishes one with CMake support
 
 if(QGC_ENABLE_BZIP2)
+    if(NOT USE_SYSTEM_BZIP2)
     CPMAddPackage(
         NAME bzip2
         VERSION 1.0.8
@@ -248,6 +288,9 @@ if(QGC_ENABLE_BZIP2)
     else()
         message(FATAL_ERROR "bz2_static target not found")
     endif()
+    else()
+        target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE bzip2)
+    endif()
 endif()
 
 # ============================================================================
@@ -267,6 +310,7 @@ else()
     set(_LIBARCHIVE_LZ4 "OFF")
 endif()
 
+if(NOT USE_SYSTEM_LIBARCHIVE)
 CPMAddPackage(
     NAME libarchive
     VERSION 3.8.6
@@ -325,4 +369,7 @@ else()
     message(FATAL_ERROR "libarchive target not found")
 endif()
 
+else()
+    target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE libarchive)
+endif()
 
diff --git a/src/Utilities/Geo/CMakeLists.txt b/src/Utilities/Geo/CMakeLists.txt
index f0e328b09ef9..bf2a906df589 100644
--- a/src/Utilities/Geo/CMakeLists.txt
+++ b/src/Utilities/Geo/CMakeLists.txt
@@ -34,6 +34,7 @@ qt_add_resources(${CMAKE_PROJECT_NAME} "kml_schema"
 # GeographicLib Integration
 # ============================================================================
 
+if(NOT USE_SYSTEM_GEOGRAPHICLIB)
 CPMAddPackage(
     NAME geographiclib
     VERSION 2.7
@@ -62,11 +63,16 @@ target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE GeographicLib::GeographicLib
 if(geographiclib_ADDED)
     qgc_disable_dependency_warnings(GeographicLib_STATIC)
 endif()
+else()
+find_package(GeographicLib REQUIRED)
+target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE GeographicLib)
+endif()
 
 # ============================================================================
 # Shapelib Integration
 # ============================================================================
 
+if(NOT USE_SYSTEM_SHAPE)
 CPMAddPackage(
     NAME Shapelib
     VERSION 1.6.3
@@ -78,6 +84,8 @@ CPMAddPackage(
         "BUILD_TESTING OFF"
 )
 
+endif()
+
 target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE shp)
 if(Shapelib_ADDED)
     qgc_disable_dependency_warnings(shp)
diff --git a/src/Utilities/Parsing/Exif/CMakeLists.txt b/src/Utilities/Parsing/Exif/CMakeLists.txt
index a4d91815ba4a..17b4b62834bb 100644
--- a/src/Utilities/Parsing/Exif/CMakeLists.txt
+++ b/src/Utilities/Parsing/Exif/CMakeLists.txt
@@ -16,6 +16,7 @@ target_include_directories(${CMAKE_PROJECT_NAME} PRIVATE ${CMAKE_CURRENT_SOURCE_
 # libexif uses autotools, so we build it directly from source files
 # ============================================================================
 
+if(NOT USE_SYSTEM_LIBEXIF)
 CPMAddPackage(
     NAME libexif
     VERSION 0.6.25
@@ -103,5 +104,5 @@ typedef SSIZE_T ssize_t;
     # Suppress warnings in third-party code
     qgc_disable_dependency_warnings(exif)
 endif()
-
+endif()
 target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE exif)
diff --git a/src/Utilities/Parsing/ULog/CMakeLists.txt b/src/Utilities/Parsing/ULog/CMakeLists.txt
index c42e5d37e6d8..59ce8a88a4b3 100644
--- a/src/Utilities/Parsing/ULog/CMakeLists.txt
+++ b/src/Utilities/Parsing/ULog/CMakeLists.txt
@@ -16,6 +16,7 @@ target_include_directories(${CMAKE_PROJECT_NAME} PRIVATE ${CMAKE_CURRENT_SOURCE_
 # PX4 ULog parsing library
 # ============================================================================
 
+if(NOT USE_SYSTEM_ULOG_CPP)
 CPMAddPackage(
     NAME ulog_cpp
     GITHUB_REPOSITORY PX4/ulog_cpp
@@ -28,3 +29,7 @@ qgc_disable_dependency_warnings(ulog_cpp)
 target_include_directories(${CMAKE_PROJECT_NAME} SYSTEM PRIVATE ${ulog_cpp_SOURCE_DIR})
 
 target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE ulog_cpp::ulog_cpp)
+else()
+find_package(ulog_cpp REQUIRED)
+target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE ulog_cpp)
+endif()
diff --git a/src/Utilities/SDL/CMakeLists.txt b/src/Utilities/SDL/CMakeLists.txt
index 22a0bd05e69f..a62e5a8718e9 100644
--- a/src/Utilities/SDL/CMakeLists.txt
+++ b/src/Utilities/SDL/CMakeLists.txt
@@ -40,6 +40,7 @@ else()
     set(SDL_STATIC_FLAG "ON")
 endif()
 
+if(NOT USE_SYSTEM_SDL3)
 CPMAddPackage(
     NAME SDL3
     VERSION 3.4.2
@@ -95,11 +96,17 @@ else()
     target_compile_definitions(SDL3-static PRIVATE SDL_MAIN_NOIMPL SDL_MAIN_HANDLED)
     target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE SDL3::SDL3-static)
 endif()
+else()
+find_package(SDL3 REQUIRED CONFIG)
+target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE SDL3)
+target_include_directories(${CMAKE_PROJECT_NAME} PRIVATE ${SDL3_INCLUDE_DIRS})
+endif()
 
 # ============================================================================
 # SDL Game Controller Database
 # ============================================================================
 
+if(NOT USE_SYSTEM_SDL_GAMECONTROLLERDB)
 CPMAddPackage(
     NAME sdl_gamecontrollerdb
     GITHUB_REPOSITORY mdqinc/SDL_GameControllerDB
@@ -107,6 +114,10 @@ CPMAddPackage(
     DOWNLOAD_ONLY
 )
 
+else()
+set(sdl_gamecontrollerdb_SOURCE_DIR /usr/share/SDL_GameControllerDB)
+endif()
+
 set(SDL_GAMECONTROLLERDB_PATH "${sdl_gamecontrollerdb_SOURCE_DIR}/gamecontrollerdb.txt")
 
 qgc_set_qt_resource_alias("${SDL_GAMECONTROLLERDB_PATH}")
diff --git a/src/VideoManager/VideoReceiver/GStreamer/CMakeLists.txt b/src/VideoManager/VideoReceiver/GStreamer/CMakeLists.txt
index 4ad33c6967c2..c4a7e16cdef6 100644
--- a/src/VideoManager/VideoReceiver/GStreamer/CMakeLists.txt
+++ b/src/VideoManager/VideoReceiver/GStreamer/CMakeLists.txt
@@ -12,6 +12,28 @@ if(QGC_ENABLE_GST_VIDEOSTREAMING)
         OPTIONAL_COMPONENTS GlEgl GlWayland GlX11
     )
 
+    if(GStreamer_USE_STATIC_LIBS)
+        foreach(_plugin IN LISTS GSTREAMER_PLUGINS)
+            if(GST_PLUGIN_${_plugin}_FOUND)
+                target_compile_definitions(${CMAKE_PROJECT_NAME} PRIVATE GST_PLUGIN_${_plugin}_FOUND)
+            endif()
+        endforeach()
+    endif()
+
+    # Build GStreamer Qt6 QML GL plugin
+    if(USE_SYSTEM_GSTQML6)
+    target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE "${LIB_PREFIX}/gstreamer-1.0/libgstqml6.so")
+    else()
+    add_subdirectory(gstqml6gl)
+    endif()
+
+    # TODO: Add Qt6 Direct3D11 plugin support
+    # https://gstreamer.freedesktop.org/documentation/qt6d3d11/index.html#qml6d3d11sink-page
+endif()
+
+if(TARGET gstqml6gl)
+    target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE gstqml6gl)
+
     target_sources(${CMAKE_PROJECT_NAME}
         PRIVATE
             GStreamer.cc
diff --git a/src/Viewer3D/Providers/Osm/CMakeLists.txt b/src/Viewer3D/Providers/Osm/CMakeLists.txt
index 6fda61451dbe..40b7515d623f 100644
--- a/src/Viewer3D/Providers/Osm/CMakeLists.txt
+++ b/src/Viewer3D/Providers/Osm/CMakeLists.txt
@@ -59,6 +59,7 @@ target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE expat)
 # protozero — required by libosmium headers
 # ----------------------------------------------------------------------------
 
+if(NOT USE_SYSTEM_PROTOZERO)
 CPMAddPackage(
     NAME protozero
     GITHUB_REPOSITORY mapbox/protozero
@@ -66,10 +67,14 @@ CPMAddPackage(
     DOWNLOAD_ONLY YES
 )
 
+else()
+    set(protozero_SOURCE_DIR /usr/src/protozero)
+endif()
 # ----------------------------------------------------------------------------
 # libosmium — OSM data parsing
 # ----------------------------------------------------------------------------
 
+if(NOT USE_SYSTEM_LIBOSMIUM)
 CPMAddPackage(
     NAME libosmium
     GITHUB_REPOSITORY osmcode/libosmium
@@ -77,6 +82,10 @@ CPMAddPackage(
     DOWNLOAD_ONLY YES
 )
 
+else()
+    set(libosmium_SOURCE_DIR /usr/src/libosmium)
+endif()
+
 target_include_directories(${CMAKE_PROJECT_NAME}
     SYSTEM
     PRIVATE
diff --git a/test/UnitTestFramework/Benchmarking/CMakeLists.txt b/test/UnitTestFramework/Benchmarking/CMakeLists.txt
index 3f95729725f7..0ba02740b9c8 100644
--- a/test/UnitTestFramework/Benchmarking/CMakeLists.txt
+++ b/test/UnitTestFramework/Benchmarking/CMakeLists.txt
@@ -1,12 +1,14 @@
 # ----------------------------------------------------------------------------
 # nanobench (Microbenchmarking Framework)
 # ----------------------------------------------------------------------------
+if(NOT USE_SYSTEM_NANOBENCH)
 CPMAddPackage(
     NAME nanobench
     GITHUB_REPOSITORY martinus/nanobench
     VERSION 4.3.11
     SYSTEM YES
 )
+endif()
 qgc_disable_dependency_warnings(nanobench)
 target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE nanobench)
 
diff --git a/test/UnitTestFramework/PropertyTesting/CMakeLists.txt b/test/UnitTestFramework/PropertyTesting/CMakeLists.txt
index 59a510ea9ab6..2a5c05350f49 100644
--- a/test/UnitTestFramework/PropertyTesting/CMakeLists.txt
+++ b/test/UnitTestFramework/PropertyTesting/CMakeLists.txt
@@ -11,6 +11,7 @@ string(REPLACE "--coverage" "" CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG}")
 string(REPLACE "-fprofile-arcs" "" CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG}")
 string(REPLACE "-ftest-coverage" "" CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG}")
 
+if(NOT USE_SYSTEM_RAPIDCHECK)
 CPMAddPackage(
     NAME rapidcheck
     GITHUB_REPOSITORY emil-e/rapidcheck
@@ -27,6 +28,7 @@ CPMAddPackage(
         "RC_ENABLE_EXAMPLES OFF"
 )
 
+endif()
 # Restore coverage flags
 set(CMAKE_CXX_FLAGS_DEBUG "${_RC_SAVED_CXX_FLAGS}")
 set(CMAKE_C_FLAGS_DEBUG "${_RC_SAVED_C_FLAGS}")