Hello =)
I’ve got issues with PipeWire audio…
On Desktop (KDE) everything works perfectly, Stereo sound, 5.1 sound… All seems ok.
But, When I put speakers config to Surround Sound output IEC958/AC3, I’ve no sound at all on any games ! (And only on games, works perfectly for the rest).
I MUST set back output to S/PDIF Digital Stereo IEC958 to get sounds on my games, but of course, only in Stereo … 
I’ve looked a lot on the internet, seems to be “famous” with 5.1 cards.
For my part is the integrated chip on my motherboard : Starship / Matisse HD Audio controller.
If I test the Konsole command : speaker-test -c 6 -t wav -l 10~
I’ve got correct results at speaker test.
Downgrade to PulseAudio solve the problem, but I would try to keep PipeWire audio if it’s possible.
Thanks a lot for your help !