I can turn off other features and work around them but the most annoying yet harmless is the flicker when you switch to an inactive app. The title bar and the window contents change their color at different frames. It requires ditching Breeze and using other theme engines/decorations altogether.
I currently use niri but Plasma has always been my go-to/backup DE. I always have it installed in case someone else has to use my PC.
It depends on people and their age (of eyes). None of my parents/elders (except an uncle; he's the only one who's had LASIK) could see the point of my 240Hz monitor.
It makes hacking easier in some ways too. Overlay any hacks. It will be gone by reboot unless you want otherwise. Also see blue-build.org <- It helps you to put all your hacks in the immutable image.
I currently use niri but Plasma has always been my go-to/backup DE. I always have it installed in case someone else has to use my PC.
[1]: https://bugs.kde.org/show_bug.cgi?id=433569