Exportieren und Freigeben bleibt hängen

"Export and release, no matter whether a film of 20 minutes or 80 minutes, exporting is not possible. As soon as only 5s
are left, it gets stuck. Has been tried with several films. PC is an i9 10900K and 64GB RAM. What should be adjusted?"

This does not come up often.  When it does, there seem to be a couple possibilties.  First is that the GPU driver needs to be updated.  In some cases, it needs to be set back to an older version.   Second, is that the GPU can be turned off in preferances.   

Using search, there was one case where a Windows update fixed the problem.

There is also the possibilty that one of the clips is has an error in it.  Try setting the work area bars around smaller portions of your time line and use the "work area only" check box in the export dialog.