Bought the LG OLED C9 yesterday. Xbox connected to HDMI 1. PC connected to HDMI 3. Sonos beam to HDMI 2 ARC
When PC is connected - arc sound is disconnected and Sonos app says no connection to tv. Choosing HDMI 2 shows the Sonos waves on screen. Disconnecting the PC, TV says "Sonos is found, and can now be controlled with magic remote".
I switched HDMI cables between beam and PC. The same problem. As soon as pc is connected - Sonos disconnects. This I think means there is no issue with the cables. Is the pc highjacking the signal? Both HDMI cables are brand new.