Error: Compatibility Tool failed on ANY game

[Zorg]

So! Ive installed Steam on Fedora 42 (having backed up my games folder and now connecting it with the new installation)

But as you can see from the title it now says Compatability tool error when i open ANY game, even if its Linux native.

As an example for trying to run Spiral Knights (non native Linux game) with Proton I got the following errors:

pv-adverb[260663]: E: Failed to execute child process ?/run/media/user/folder/SteamLibrary/steamapps/common/Proton Hotfix/proton? (Permission denied)

or

pv-adverb[264159]: E: Failed to execute child process ?/run/media/user/folder/SteamLibrary/steamapps/common/Proton - Experimental/proton? (Permission denied)

What could be the root cause of this? How do i fix this? Is anybody else encountering this error?

[Zyro]

Did you try to use another Proton version?
Are you running both Proton and the games from a Linux native file system?