Search for ‘Active optical HDMI cable 20m’, you’ll be greatful for extra on each end and the cable is very thin cable, just never kink it. You can get up to 48Gbps 8k 60hz 12 bit color depth. This cable would be easy to hide under a rug or tack along the floor board around the walls or even ceil.

If you don’t need crazy resolution and frame rates you can get wireless HDMI extenders but they can get pricey.