Reviving this thread one year later as I'm facing the exact same issue with my MBP 14" M1 Pro (macOS Ventura).
I'm connecting my MBP 14" ---TB3 cable---> Caldigit USB-C Pro Dock ---DP-HDMI adapter + HDMI 2.0 cable---> TV.
The TV shows up as an output device, but selecting it doesn't output any sound to the TV whatsoever.
Tried an HDMI TB3 Dock (no DP conversion) with the same Macbook and it works fine.
Did anyone find a solution to this months later?