good to see that it resolved.
I got the same error a few months ago when i didn’t add my system python into PATH (not to be confused with python i installed using homebrew, which didn’t solved my problem when added to PATH).
If you follow the prover installation guide, you will note that step 2 prompt you to add python into PATH or else strange errors will occur.
What i suspect happened in your case is that you downgraded python so that the path to the python in your $PATH was pointing to an absence file, which led to this error.
Just a guess, dont know if this is really what happened there.