I did some testing with the SharkRf link app on my iPhone 12.
Szenarios with test results (it seems that there is a an issue with Bluetooth in speaking mode)
- AirPods 2
- good quality in hearing but bad audio quality in speaking (could provide sound file if that helps)
- Apple CarPlay (Bluetooth connect with the car)
- good quality in hearing but bad audio quality in speaking (could provide sound file if that helps)
- wired headset
- good quality in hearing and good quality in speaking
- internal speaker/mic (hands free)
- good quality in hearing and good quality in speaking