I've got an older Yamaha receiver paired with an LG UK7500 and I had no end of issues with arc between the two. Eventually I ended up just abandoning the entire thing and have really weird settings that somehow control the receiver using CEC but pass the actual audio over optical. Set up wise mine will pass through 4K video but not HDR, so I have the switch running through the receiver then everything else through the TV which gets the job done giving the best image and passing at least DD through sound wise.

All the playing I ended up doing I found Dolby digital+ to be the common fault with mine, I could get TV sound just nothing from Netflix or Amazon or anything utilizing DD+. Occasionally I could force the Netflix app to restart and get sound but it was always short lived, it was as if the trigger to tell the receiver that's what it was getting just wouldn't fire and it saw nothing via the arc connection. All other formats were fine from all sources it was just DD+ that I never got to work.