Since the latest update (16/09/23) I have no notification sounds.
Other threads mention when music playing, it might make notification sound. But when phone isn't being used, no notification sounds.
All options are turned on for sounds. No battery saving. No bubble heads.
It's super annoying!!!!
I found that my galaxy wearable app updated for my watch and set on the notification setting "Show only while wearing". Shows notifications on your watch only while it's being worn. May not be everyone's problem but it helped me. Turning that off returned all the notification sounds back on my phone.