All the various windows UI frameworks are stable, but not supported and not receiving new updates.

That's the problem.

And what makes matters worse is because of all the shifts, the documentation throughout MS is in just varying states of outdated. For example, this document which recommends using UWP [1] to handle high dpi problems. But of course, UWP (which was the right way to do gui in Win 10) is now defunct for win ui.

[1] https://learn.microsoft.com/en-us/windows/win32/hidpi/high-d...