I have the S10+ and noticed that if I have my bluetooth headphones on im not able to receive any notification sound. Once I turn it off my notification sound works. There has to be some way to have sound and not have to turn my bluetooth off. As well if im on a call and get a text message it doesn't pop up the screen just stays black
Can you tell me the model headphones you're using? Some headphones have a setting where your able to adjust the notification from the app.
Have you tried turning up the notification volume while your headphones are connected?
When you're on a call and the phone is close to your face, the screen turns off to keep your cheek from causing havok to the phone. This screen turning off seems to be different from the usual sleep mode that happens when you press your power button.
If you're talking about hands (and cheek) free calling, then it might have something to do with how edge lighting works while you're on a call? Not too sure about that one.