Frustrated beyond belief ! I have a pretty simple setup Nvidia Shield (2019) → Samsung Q9FN → Sonos Arc. If the Sonos is connected to the Q9FN ARC HDMI port, 75% of the time when I switch streaming apps, HULU to Netflix, Prime to HULU etc, I get video but no sound. Force quitting and restarting the streaming app fixes it. Never had any issue with my previous Playbar. I’ve tried lots of cables, initial power on sequences, different HDMI TV inputs, etc. Nothing worked.
When I use the HDMI to Optical adapter, it’s perfect. Perfect if you don’t care about Atmos or DD+ that is.