I have a new twist on the issue: there is no alarm sound, no ringtone preview audio in the swipe-down menu slider, the pulldown menu in the Messages app freezes the application, but audio message playback in WhatsApp works, and Nettiradio can play audio through the loudspeaker. I assume Bluetooth audio works, although I can’t test it right now.
I suppose some application reserves some sink or something like that, what should I do check out now?
Edit: There’s no WhatsApp message notification sounds nor email sounds.
Edit 2: The screen went black when I was browsing journald, so I had to force reboot the device. Or just reboot, I’m not sure which one. Oh well!