Unity starting from 2020.0 is unusable for me

After every major action (like loading scene, creating prefab, playing, etc) "Hold on" window pop up and editor freezes for a few seconds. Now when I imported two huge asset packs (>1gb each) I can't open any scene with objects, "Hold on" window pops up with infinite PlayerLoop or UpdateScene loading. I tried to wait, but even after an hour editor doesn't unfreeze. There's also an issue that the editor crashes when there's at least one skinned mesh in the scene, but I fixed it with increasing TdrDelay
None of this were happening in previous versions, I successfully used exactly the same assets in my previous projects, more than one character with skinned mesh, etc
I was able to load assets' showcase scene once and noticed that the performance is much better now, but unfortunately I have to back to 2019 LTS version

 

I've had issues like this in Windows 7 (now primarily using 10 but not long enough to know whether the same thing happens). What I did to work around it is when loading Unity Editor, selected the process in Task Manager - then when the editor would sit there with the popup but nothing apparently happening and like no CPU usage, there was a second Unity.exe running in the Task Manager processes list. I'd know that was the one to close because I had the initial process selected and the new one wasn't - before I figured that out it was guesswork and it's not always the second one listed. So I'd click the new one and end the process and the popup status/progress dialog would disappear and the action would complete / the editor would unfreeze and continue as normal. I'm not sure how far back the issue exists or what exactly causes it to lock up like that, but I first found this "last chance tactic" several alphas ago (2020.2). It has let me save things I've done that I would have lost otherwise if I had to just force the editor to close (which was how I stumbled on this to begin with).

 

Unity 2020 is also unusable for me Hold on lasts forever and pops up every 2 minutes. This is pretty ridiculous.

 

I don't know if it's entirely true, but I noticed that Unity has problems with old AMD GPU. I had such card and the editor was consistently crashing as well as games made in Unity. All my friends with old AMD GPU have exactly the same problem

 

The Hold is true, It will not go away and happens every-time my unity editor stops playing. I had noted that it was about every 2 mins. It just happens to coincide with every time I ran my game in the editor.