I tried switching from Gnome to KDE Plasma on my Thinkpad. From first few minutes of use I like it quite a lot, but OMG the random flickering (notification windows, bottom bar). And it cannot be a graphics gpu/driver issue, as many transitions (transparency, moving windows) are nice and smooth.
Also, I just opened a text file and the editor (Kate) just stopped responding. Tried to close it, got a "Terminate application" dialog, but nope, after several attempts it's still up and can't be force-closed. Not even `kill -9` works.