ARC has been too dicey for me. I will never tell anyone to rely on it as all it takes is for any device to be updated and the system crumbles. Same thing for settings. I've see techs set it up and it falls apart monthly as the owner either on purpose or by accident flips a setting.

Always get the optical cable in the setup. Then again there are folk that demand that ARC work and you know to keep your distance and never let them hear it might work. They'll dog you for years.