I did find a way to remove Rosetta again, but it involves the Recovery because the files are SIP Protected.
Obtain a list of files/directories and LaunchAgents with: pkgutil --files com.apple.pkg.RosettaUpdateAuto
Save them in a way that you can access them in the recovery
Boot into recovery
Make sure your disk is mounted
delete the files from Disk
reboot
I hope this helps everyone who is in the same Situation as I was.
Best Regards
Timo