I have a Steam deck and I have problems like this when I use the official dock on my main monitor.
However, I have no problems with other monitors or a 3rd party dock with the same monitor.
All that to say I would try new cables, a different dock, etc but thats just a guess.
I picked up a Denon DNP-730AE network audio player on ebay and I run Tiny-DLNA on my server where the music files and playlists are stored.
Works great and sounds great.