Bought S21 Ultra a month ago. I've been playing music with no problems during that whole month. After the update that I was recently offered to install, eventually, after listening to like 10 songs, the music audio just is not working, even though the app still shows that the music keeps on playing. I'm using Samsung Music app. I use a bluetooth speaker. I tried to turn it off and try whether this bug appears on my phone speakers, and it does, they only fix so far is to restart the phone. Reinstalling the app does NOT work. Eventually after playing a few songs the same bug appears, so I have to restart the brand new phone all the time. I don't know if it's the new update problem, but I didn't have such a bug before I installed the update.
@Skirtap: I'm sorry to hear that you're experiencing this issue. Have you noticed if the music stops playing under any particular conditions e.g. when the phone goes idle, or is it random? As a troubleshooting step, please head to Settings > Sounds and Vibration > Separate App Sound > Turn On Now > App > Samsung Music > Audio Device > Select your speaker. Does the issue persist with this setting in place? If so, head to Settings > Battery and Device Care > Battery > Background Usage Limits, and make sure that Samsung Music is not limited in any way.
The music audio stop always has happened after a song ends. For example, I was waiting for the next song to start, but for some reason nothing was played back for like 30 seconds after the last song had ended, so I turned on the phone to check what's going on. I open the app and see that the song is playing, but there's no sound, I try to select a different song, and there is still no sound, so I have no choice but to restart the phone.
I'll try out the suggestions of yours, thank you.