M
Also noticed heavy flickering on plasma ALL THE TIME so I switched to gnome and the issue was smaller, mostly limited to sites where video was played. Went back to plasma and turned on system window decoration (transparent one) and the problem is gone. Not on gnome however, turning system window decoration did actually nothing… in this DE, windows decoration was not applied and flickering was present on videos pages.
So I guess the issue is with composer and windows decoration. Chrome with own window decoration has no such problem. Also I can turn on firefox extension that gets rids of system window decoration and uses own (or lack of it), so it would look like on windows and there is also no problem. Only vivaldi has such issue so I guess it can be fixed somehow.
I like to turn off window decoration because it takes space and does nothing, but at current stage I can't.
