What I meant by ‘allowing open access’ was as follows.
A small warning window popped up when I opened PsychoPy for the first time after upgrading it the v3.2.4. I clicked the ‘allow’ button on the warning window. Now, this warning is not appearing anymore, so I don’t remember/replicate the exact warning message, but it was about if I want to allow open access for the program that is from the unidentified developers.
I think you can find this message also on ‘Security & Privacy’ panel under System Preferences as in the image below if you missed this warning for some reason or when PsychoPy refused to open.
Others mentioned adding a keyboard on Input Monitoring, but I couldn’t add anything there, which looks as in the bottom image. I don’t have any issue right now using keyboard input on PsychoPy without adding a keyboard in this panel.
I don’t know if my solution works for everybody, but this worked for me at least.