I have had my S24 Ultra for about two months ... no issues until a few days ago (and perhaps unaffiliated with this issue, but the day after a system update on Feb. 14th) ......... originally I had no issues playing music or audio through the usb c headphones .... initially I used an adapter for usb c to 3.5mm because that is what most of my wired headphones were ... since this issue developed I have bought a pair of usb c DAP compatible headphones .... but those do not work either when I plug them in .... everything always only plays through the external speaker.
I have re-booted. .... Again it is only 2 months old and I have had a protective case on it so that the usb opening itself should not be dirty or contaminated ...... I have searched for app and system updates and firmware updates ... everything seems up to date. I have initiated "Developer Options" under settings and disabled "USB Audio Rerouting". Please provide any other actions I can attempt please.
