IFI I-Purifier. Use that exact same setup on my system with toslink coming out of tv. Cheap and makes a huge difference. All you need for a situation like that IMO.
you use a Toslink to mini toslink and that end plugs into the side of the I Purifier. The Ipurifier plugs into the Coax input of whatever DAC you are using. Way more solid less digital sound. Even streaming YouTube videos sounds passable.