Hi guys,
depending on the app, permission for ‘Nearby devices’ or ‘Sensors’ is required for Bluetooth devices!
If you have not given an app this authorisation, maybe it will not pair the Bluetooth device at all or perhaps sometimes and then hold the connection for an unreliably long time.
Examples:
Session Messenger: may use permission: Sensors (not ‘Nearby devices’).
Signal Messenger: asks for permission: Sensors (not ‘Nearby devices’).
SimpleX Messenger: may use permission: Sensors (not ‘Nearby devices’).
Threema Messenger: requires permission: ‘Nearby devices’ (not ‘Sensors’).
But: Session + SimpleX also work without this authorisation if the Bluetooth connection to the Pixel Phone has already been established before the call.
Signal asks not because of Bluetooth functionality but for screen orientation.
Authorisation for sensors is helpful/required for these (and similar apps) in order to establish the Bluetooth connection afterwards.
Scenario: You start the voice chat (accidentally?) without the BT headset switched on, then want to use it and it is not found during the call.
That's my experience, hope it helps also for you! ;-)