I’m giving Bazzite a try right now reviewing it, and I’ve go NO audio.
It seems Bazzite is not seeing my Nvidia RTX 3060’s HDMI audio out in my system’s sound setup. Even though other audio out sources work.
So I’d like to know how I get bazzite to see the HDMI audio output in the system control panel, not just for myself, but others that may be asking this question.
Im having the same issue today on a RX 580. Audio works in Desktop mode but not Gamemode. 
Desktop Mode, Gamer Mode?
I don’t see where that is controlled in the OS, as you’ve been the only one to reply to my question.
And if your referring to " Steam Gaming Mode" as the thing the denotes between Desktop and Gamer Mode, well I picked Desktop mode. As I want hardware support.
If this is true then there is a bug in Desktop Mode with HDMI audio support.
It was fixed a day or 2 ago, randomly, maybe by an update? Not sure, but Desktop mode had audio, not gaming mode.
It works now, however!
Yeah, just had an update go through and now it is selectable.
So it now seems fixed, I’ll update the note that HDMI will be iffy in my review of Bazzite
Nope, it seems to work and at other times not work.
So yeah, it is flaky for me at this point.