Computer freezes for 2-3 seconds

OldNavyGuy said:

You can also check the Windows Event Logs for errors. Right-click on the Start icon, select Event Viewer, expand Custom Views, and look in Administrative Events for entries around the time it happens.

Here is the Event Log. The problem appeared at 10:55.

Yes, there is the rma. What I suggested doing was for a software freeze. It's not worth looking for a hardware freeze.
In your post 8 I don't see the KB4568831 Cumulative Update, install it, it may solve a freeze problem : KB4568831 Cumulative Update Windows 10 v2004 build 19041.423 - July 31

edit: I'm not 100% sure but if it doesn't freeze in safe mode anymore then it's software freeze.

The Event ID 642 errors are related to Catalog Database in C:\Windows\System32\catroot2 in Windows 10 2004.

I deleted all files in catroot2 in the Recovery Environment (they are re-created on boot).

I then disabled Windows Search and Indexing (which was replaced with Everything from voidtools a long time ago).

That reduced the number of 642's significantly, but did not eliminate them.

Well, finally Dell replaced my hard disk and my motherboard. I hope this will finally solve the problem.
Thanks to all for your help.