I have Ubuntu 20.04 on an Intel NUC NUC11PAHi5, and can't get HDMI audio output to work. I did notice if I suspend and resume, 2 channel HDMI audio will work, until I reboot, but not 5.1 channel HDMI audio. Is there any instructions to get audio working properly?
I did fix the aux jack that was also not working by following this,Install Realtek Audio drivers in Ubuntu 20.04 (Intel Nuc nuc10i7fnh)
I have the same NUC and was able to get 5.1 working in 22.04. I ended up using a USB-C to HDMI cable but I still needed to suspend and resume, sometimes several times. I had issues with channels being swapped too (e.g., center channel playing in front right) which fixed itself through suspend and resume.
Unfortunately, it doesn't seem like there's a proper fix (at least I haven't found one) and pipewire in 22.10 isn't any better. In fact, I can't even get 5.1 to work at all, and it still takes suspend and resume to get 2.0 to work.