So, after tinkering around a bit i actually got something to work again. Hurray
My trick was to go into the windows sound mixer and reset the settings to default there. Opera did not show up at all before doing that (and yes i went through all audio output devices just to be sure), then i thought "You know, its a pain because of all the programs that are configured on a different output device, but i'll give it a try".
for those finding this in the future
I'll probably keep updating this topic, just in case anyone comes across it. For now (Update 100.0.4815.82, dated 26.07.2023) it seems to work to do the following:
Windows-Settings -> System -> Sound -> Sound Mixer -> Reset to default (At the bottom)