I would bet in Avalonia UI. It's like WPF but cross-platform. https://avaloniaui.net/

SDRPlay is using Avalonia for its SDRConnect desktop UI. That's the one native application based on Avalonia I've spent significant time in.

It's ok. I give it pretty high marks. There is a good deal of "lowest common denominator" in it, naturally due to cross platform abstraction. But, it's generally nice, and commercial licenses are affordable.