I am a Sonos Dealer and Pro AV installer - We have been running into many installations that call for a Sonos Amp powering wired speakers in a Family room Setting. Normally we run an HDMI from the TV ARC Channel to the Sonos AMP HDMI input. Works perfectly and an easy Customer experience using their Providers remote. We have had issues dealing with installations that only have a CAT 5-6 cable running from the TV to an equipment closet where the Sonos AMP will be located. We have tried many HDMI Baluns to get the ARC channel to the AMP with limited success. I have finally found a Balun that passes ARC perfectly and reliably. We used the Vanco EVEXARC unit. This is an FYI since I had trouble finding a product that worked properly. If you are a Dealer and your supplier carries Vanco it is pretty affordable for a specialty Balun. I am sure there may be other Baluns that work but I have stopped looking.
Happy Installing !!