This was posted in the fourm about 4 hours ago:
ADMINs / MODS:
IF THIS DOESN'T WORK FEEL FREE TO DELETE THIS POST.
It is the installation of the Creative Cloud app (necessary to install Photoshop) that is the solution, rather than the installation of the Photoshop trial.
It worked for me! Thank you!
Unfortunately, even installing the Creative Cloud does not change the error here. :o(
Strangely enough, all software manufacturers manage to adapt their products to Monterey in good time. Except Adobe again. My subscription to the cloud will expire in June - I already know what I'm going to do.