If camera access and microphone access have been toggled off, it should automatically turn back on when the camera app is manually opened.
The same should happen if microphone access is toggled off and you initiate/receive a phone call. It's frustrating having to struggle to turn on microphone access if you receive a phone call and the phone is locked.
Agree 100% with you, once you have safely entered your phone, pin, password or fingerprint, the user's access must be automatic but, continue blocking to external sources
