Got a new S21 Ultra a few days ago, and I am noticing some odd behaviour with my USB C headset.
The headphones seem to work fine with calls.
With media/apps - Often with the headphone plugged in, the audio comes out the phone's main speaker. Disconnecting the usb c and reconnecting it usually forces the audio to switch to the headset.
However, if I pause video/audio for more than a few seconds or switch apps the audio jumps back to the main speaker.
I do get an android notification saying "USB device not recognised" when it stops working.
Tried it on an S10, I don't get the "unrecognised USB notification" nor the audio reverting to main speaker after a pause. It does however switch to main when you switch to a different app. So Im guessing either the headphones or the Samsung USB-c app are the issue. May just bite the bullet and just get some Galaxy buds.