I get your point - when headphones are connected, the phone's mic is used to capture voice rather than the headphone mic. I observe the same behaviour.
Best option is to provide feedback to Samsung Support via the Samsung Members app --> Support --> Feedback.
@Ventor Activate Nearby works in Voice Recorder app, but not for Screen recording.
Hi! It's November 2022 and I have the same issue with my bluetooth headset on Galaxy S10. In the last few weeks I have lost ability to record sound from bluetooth microphone (Whatsapp, messenger or Recorder, whatsoever), while recording only microphone from the phone is working.
Headsets are working fine, tested