I would also like a solution to this problem,
I think in an ideal world Acuity would generate a random door code, I'd be able to include this in booking confirmation emails with the smart tags. and this would sync with a 3rd party lock system, we have TTLocks installed but would be happy with any integration that handles cancelations or amendments to appointments.
At a very minimum a pin in the confirmation email, then I build an automation that uses the email to create a code.