My phone - a Samsung Galaxy running Android 11 (with their One UI v3.1) - for reasons I have been unable to discover, has recently stopped playing any sounds for notifications (e.g. e-mail, messages, etc). The notifications appear just fine, it's that there's no audio alert sound that goes with them like usual.
I've checked all the relevant settings and options I can find, and none appear to be in a state that would cause this. It's not on silent mode, not on do-not-disturb (and no timed schedule for that set); I have a notification sound set; the notifications volume level isn't turned down; media volume limit is turned off; I haven't restricted any apps from showing notifications. I've done a keyword search in the Settings app for anything to do with 'volume', 'notifications', etc. but not seen anything else other than what I already looked at.
Yes, I've even restarted the phone - more than once. It's even had an Android OS update installed since this started.
I don't know what else to look at or try. Anyone got any ideas? I want to fix this because I keep missing messages and stuff.