Some aspects of theming are messed up, like the spacers on my GTK4 drop menus are just flat gray rectangles (they look like placeholder assets). Also launching some programs after a fresh boot now take an inexplicable long time, but only the first time. So for example, if I reboot and launch Firefox or Nautilus it will take an extra 5-6 seconds. Every subsequent time any slow launching program will be fast so long as one of the slow launching programs has been started.

Finally, not a messed up thing, but there is just needless clutter of stuff in my config files, now, since I've got KDE, Gnome, and actually a couple other DE things laying around, now. Mind you, this is all after I've already uninstalled KDE.

Edit: I thought about what I wrote and it occurred to me some of that stuff might be because of bad gtk4 config files. So I deleted them and rebooted. The theming is correct again as far as I can tell, but the slow launch stuff persists.