Another thing you should try is Verfiying your files if you havent.
Even if you download all the files per se when you swithc the versions, sometimes it dont do it properly.
So do the first steps I said before, but on the bar you should look for "local files or "installed files" again hard to say for sure as my native isnt English. Should be the 3rd choice.
When you click that menu you should see 3 choices.
1 with installation size.
1 with backup of files or security copies.
1 with check for errors in the files or verify the files. --> this one you pick.
then it will check all the files, which can take some time if you got an old rig.
Should a file be incorrect the game will reload all those files and boom you should be ready to go.
Also have you installed the latest updates for your gpu?
Because sometimes some of the versions of files is causeing issues.