> but worst case I'll run a Wayland compositor on my X11 server for that
This is actually surprisingly easy, too. My first experiments ran a wayland app in cage ( https://github.com/cage-kiosk/cage ), but in order to better handle multiple windows I switched to sway with a lightly tweaked config, and other than some input weirdness (I think it struggles with modifiers held while switching focus) it works pretty well.
(And yes, I'd rather do that than go all in on Wayland)