Microsoft is better stop doing "open platform" virtue signalling and start working on improving sandbox, and usability for the Microsoft Store etc., now the Win11 MS Store is just a chaotic place that non-sandboxed exe installers provided directly by software vendors, partially-sandboxed msix win32 "apps" and fully sandboxed uwp apps are in the same place.
Apparently the situation is even worse: now MS is trying to let devs migrate to Windows App SDK by not providing support for .NET 5/6 and WinUI 3 to UWP projects.
Although Windows Sandbox is good enough to run traditional Win32 programs with rock solid isolation, it's far less elegant and will consume far more resources compared to UWP apps, also the immersive "rail mode" mentioned in the overview video isn't documented AT ALL.
Update: The most famous unofficial Telegram client on Windows, Unigram, is planning to migrate to WinUI 3. 
Now the last hope for modern Windows app development is probably powered by the Flutter community, why would Microsoft throw away the awesome platform…
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