So I didn’t do anything after reading yesterday. This morning I checked NVidia Experience for your tips, but I didn’t activate the game option. Started the sim with the same problem as yesterday. PC restarted and everything from Nvidia to the current driver uninstalled. PC restarted again and Sim started then it ran smoothly with the medium settings. Then I spent the morning gradually adjusting and checking the old settings again. Now it’s back to normal. Although it was not selected in the experience it must have been because after the deinstallation it now runs perfectly again with everything on Ultra.
My conclusion to this is now the following, since I only use this computer for the FS2020 and nothing else seems to make sense in this case only to install the NVidia driver and nothing else. Expirience really doesn’t seem to be needed there.
Excuse Asobo and Microsoft for suspecting you!