I have no idea personally, but I’m hoping this is glorious flame bait
Qt all the way. Funny thing is that if you choose to use GTK on Qt it looks decent but god forbid you use Qt on MacOS Gnome you have a terribad experience.
Xaw3d programs on Motif desktop.
I myself currently use a qt Desktop (Plasma6) and would always choose a qt app over a gtk one
I have a Qt app on GNOME https://github.com/jeena/FeedTheMonkey and it’s much essier to code wit QML and C++. But it looks quite terrible.
That is why I chose GTK and libadwaita for my next app. Looks terrific, but it takes me ages to learn how to use it, even though python is much easier than C++.