Anything related to WinUI, WinAppSDK, CsWinRT, C++/WinRT is a sea of bugs, broken tooling, and unfulfilled promises, that no one should bother with.
Easily confirmed by going into their public repositories over at Github, or community session recordings over at YouTube.
For those using .NET, keep using Windows Forms or WPF, or reach out to Avalonia and Uno.
For those using C++, the aging MFC has much better tooling as incredible as it sounds, or use instead VCL/Firemonkey (C++ Builder), Qt, wxWidgets,....
For anything else, whatever bindings are available on top of plain Win32.
Programming Windows, by Charles Petzold
Programming Windows with MFC, by Jeff Prosise
COM / DCOM Primer Plus, by Chris Corry Vincent Mayfield John Cadman