Comment 154 for bug 2009136

I'm coming back to this topic just to add what worked for me.

I had to disable Wayland in order to get audio up and running through HDMI again, following the instructions at

https://linuxconfig.org/how-to-enable-disable-wayland-on-ubuntu-22-04-desktop

I'm not sure why this helped, but at the moment I'm just happy that I have HDMI audio back!

Hope this helps someone else.