The Apple experience, worth every penny…
That output is what you often get if Matlab is not allowed to low-level access the keyboard or other input devices. Either that, or simply keyboard input silently not going through. I had the same yesterday after installing R2020b. I followed the procedure described here:
Now it works again. However the entry for R2019b, which is still installed and nothing has been changed by myself there, disappeared, so i assume it fixed R2020b while breaking R2019b, or the security GUI simply is confused now. This on a brand-new macOS 10.15.7 installation. I haven’t seen so much sadness since Microsoft Windows Vista, although Vista was a masterpiece in design and quality compared to macOS Catalina’s security workflow.
The “default keyboard not detected” however, i can’t reproduce on a touchbar MBP 2017 …
Can you retry with this fresh PsychHID. This one is built on Catalina with the 10.15 Catalina SDK. Maybe it makes some weird difference:
https://github.com/kleinerm/Psychtoolbox-3/raw/master/Psychtoolbox/PsychBasic/PsychHID.mexmaci64