This seems to be the full log this time. While there is not much of a clear reason for the crash, reading again the the 1st post, you mentioned on changing the CPUs + mobo, and my question is, did you reinstall windows completely? Because there are reports on things getting weird letting Windows doing the update for the new parts and letting some garbage behind that causes instability. If you didn’t reinstall Windows I would advice to do so. If you installed, then the only thing is to keep sending the crash reports when the screen appears and hope for the fix. Did you tried with UE4.22 preview 6? Also, UE4.22 will release this week, so it might be good if you can also test with the preview and if it still crashes, keep sending the crash reports.
Don’t forget to backup your project if moving to 4.22, because you won’t be able to revert back to 4.21.