Are you on Ventura?
If so try resetting your Preferences. Go to Photoshop Preferences/General and click the reset button.
I am, but it started a while after I installed Ventura.
it's working again Thanks
Did it resolve on its own or did it require the reset?
My idea was, is the problem the Creative Cloud app or my Mac. So I installed the Creative Cloud app on a Macbook-pro and installed Photoshop as well and there the Library was opening correct. So I reopened my Mac and then there the error was disappeared as well, why I don’t quite understand.
I didn’t use your solution in the first place because I was uncertain about the results afterwards, would all my settings be the same?
No settings are unique per computer. If you installed PS over a previous version, previous preferences may be interefering. A reset is recommended.