Also have this issue using the following:
Zotac Trinity 3090
Sony Bravia A80J
Audioquest 48Gpbs Cinnamon HDMI cable
Under 4K 120Hz works perfectly.
At 4K 120Hz produces either no sound, or the weirder normal sound, then the audio distorts and almost crinkles and tears within itself, then eventually reverts to normal. Issue happens with multiple 48Gpbs cables that are tested successfully for 4K 120Hz. Does not occur when headphones are plugged in (within the headphones themselves).
All drivers are totally up to date. Has never worked perfectly on any version.