Big Sur: PDF Service shell script cannot call python
I have discovered that Big Sur will graciously allow a script to execute in a PDF Service, if the script is put inside an Automator workflow saved as an APPLICATION. Saving as a Print plug-in, workflow, or other type will not work.
Use the 'Run Shell Script' Automator action, and place the script in there.
Whether the script can call another script with the necessary permissions, I have not tried.