I have this for a few weeks, but Telegram sound just stopped one day, (not after an update, just one minute it worked, the next gone), no sound at all, no notification sound, no video sound, nada.
All other programs including the OS sound works just fine.
No, I didn’t change this, that’s the weird part, I didn’t change anything. I have no idea where to find the Performance settings you show above, never saw them on my system. I didn’t install any of the programs you mention.
ok, you never did state which Telegram version you were using other then 4.3.1. Was it the flatpak, snap or Telegram desktop for Linux directly from Telegram(this is the one that I use) on Debian Bullseye with pulseaudio.
ok, I’m going to suggest downloading a complete new package from TG directly.
Delete the TG folder you are running it from AS WELL as /home/yourusername/.local/share/TelegramDesktop/
Then extract the new package and run again, logging in etc.
Suggestion, when you boot do you have an alternate kernel available?
Maybe a kernel downgrade would help? I seen where it had helped other KDE plasma users on different Ubuntu version and older TG versions.
There was also this link, not your exact problem but an audio issue with TG on KDE none the less:
Might be a place to look around.
One other possibility, have you tried the web api with your browser?