check your HDMI Cables! I had the same issue with my C1, Denon Soundbar and Shield Pro! and it was the cable! i searched on amazon for Certified HDMI Cables EARC compatible
https://www.amazon.com/dp/B08TGG316Z?psc=1&ref=ppx\_yo2ov\_dt\_b\_product\_details
Since your TV supports HDMI 2.1 I'd be sure any cables plugged in the TV support that. I've seen this cable recommended: