[2020] problems with objects flickering in game

Try adding the launch options -noWorkshop and -disableMods in Steam. Does it happen then as well?

https://support.steampowered.com/kb_article.php?ref=1040-JWMT-2947

If yes, then your best option is to post on the official support forums, as we're best able to help you out there.
https://forum.paradoxplaza.com/forum/forums/support-bug-reports.879/

If it's gone, then we're looking for a mod causing this. In that case I'll need your output log to see what's going on. This guide explains where to find it and recommends a few sites you can upload it to, since we can't attach files here on Steam.

https://steamcommunity.com/sharedfiles/filedetails/?id=463645931&searchtext=log

Perfect! I'll join the post on the forum then, so I can keep up with Andrew's responses and don't suggest the same stuff to you here. ^^