I don’t know about the volocopter, but I can help you with the FBW:
The exact path to re-enable flight assistant for the FBW
Community\flybywire-aircraft-a320neo\SimObjects\AirPlanes\FlyByWire_A320_NEO. There you will find the flight_model.cfg. Open it with notepad, ans scroll down to the section "[FLIGHT_TUNING].
Three lines down, you will see disable_assistances = 1. Change the = 1 to = 0 , click on file in notepad, then click save.
If you can’t find the entry, click on edit in notepad, click find, then type “disable_assistances” in the field, then hit next. It should take you right to the entry in the .cfg.