(Xbox) I’m having the same issue. I have an astro a40 headset paired with a mixamp. When i have the headset plugged into the mixamp (which is plugged into the tv via optical cable) I get no audio at all but if i plug it directly into the controller the sound works. This works but its not optimal as the audio can be rather quiet even with ingame audio settings at 100 and the mixamp allows me to adjust it further.