Looks like QT6 does not support UWP:
During this year’s Microsoft Build conference Microsoft announced the
unification of Win32 and UWP for their IoT offering. In general, it
looks like Microsoft is stepping away from their strict stance about the
usage of UWP technology and the Windows Store. Getting a classic Windows
application into the Windows Store is much easier nowadays and will be
even simpler in the future. Microsoft’s new direction in their IoT
offering will bring more “classic Windows development” into the IoT
world and there will be no need for a dedicated UWP port.
Supported Platforms
https://doc.qt.io/qt-6/supported-platforms.html
https://www.zdnet.com/article/microsoft-continues-to-try-to-unify-win32-uwp-windows-apps-with-project-reunion/
Microsoft is continuing to forge ahead with its plan to try to close the divide between Win32 and Universal Windows Platform (UWP) apps. This year, its strategy around this is getting a codename — “Project Reunion” — and more of a formal structure, which Microsoft is announcing at Build 2020.
https://www.theverge.com/2020/5/19/21258697/microsoft-windows-project-reunion-win32-uwp-apps-apis-build
Microsoft has been working to bring win32 desktop apps and its Universal Windows Platform (UWP) apps closer together in recent years
https://winaero.com/project-reunion-aims-to-unify-uwp-and-win32-development-on-windows-10/
Project Reunion is a new platform that extracts Win32 and UWP APIs from the OS, and offers them in a NuGet package manager way instead. It will deliver modern Windows features to developers who use C++, WPF, Windows Forms, UWP, and React Native to build their apps.
https://forum.qt.io/topic/147272/preparing-app-for-microsoft-store-qt-6-cmake/2
set_property(SOURCE AppxManifest.xml PROPERTY VS_DEPLOYMENT_CONTENT 1)file(GLOB ASSET_FILES "${CMAKE_CURRENT_SOURCE_DIR}/assets/*.png")
foreach(asset ${ASSET_FILES})
set_property(SOURCE "${asset}" PROPERTY VS_DEPLOYMENT_CONTENT 1)
set_property(SOURCE "${asset}" PROPERTY VS_DEPLOYMENT_LOCATION "Assets")
endforeach()
Porting qt based qml app to windows store app
https://stackoverflow.com/questions/34203806/porting-qt-based-qml-app-to-windows-store-app
The Microsoft Store is officially open to all Win32 apps
https://www.xda-developers.com/microsoft-store-open-all-win32-apps/
Ads are coming
How to create a MSIX package for a Win32 application without an installer
https://stackoverflow.com/questions/71036774/how-to-create-a-msix-package-for-a-win32-application-without-an-installer
https://stackoverflow.com/questions/64702212/how-to-build-an-msix-from-comandline/64715653#64715653