That is exactly why I use Delphi when doing GUI apps on Windows. Single GUI framework that works like a charm for more then 20 years. It is very unfashionable to say mildly but it is the fastest tool to get things done for Windows GUI apps.

You could equally just pick one of the above commentor's list and use it for 20 years (minus a few for the relatively new ones). They all still work, whereas when Apple transitions they remove the old option.

I actually tried most and ended up with Delphi as ticking most checkboxes in my big list list. Granted I am an ISV and could care less about what other think about popularity of the tools I choose. Always pick what suits me. As for finding developers: that does not seem to be a a problem if one knows how/where to look.

That can be a problem as well. My main product is a WinForms app and I have spent a huge amount of time making it work well on high-dpi screens.

I feel like I hit the sweet spot by only ever using WinForms, then getting out.

Their framework strife seems like a manifestation of their depiction in this classic: http://bonkersworld.net/organizational-charts

Is WPF still a good option? It looked like Microsoft put a lot of weight behind that for a while, they even made parts of Visual Studio in it. But I haven't heard anything about it for years, I guess it got replaced by UWP? Does UWP use XAML too?

UWP is getting better but last time I looked it still had some weird restrictions. For many things WPF is still your best bet because you can be pretty confident that you will be able to do what you need to do.