So I've bought a new TV which, unlike our other TV (an LG), doesn't have an app for Google Play Movies (something I overlooked prior to buying!). So I'm trying to find the best option for using this on the new TV; requirements are for it to support (and properly display) a 4K HDR picture and support discrete surround audio (5.1 minimum).

I've tried using YouTube to play movies bought on GPM, but that doesn't support discrete surround.

Our current streaming devices are an Apple TV gen 2 (no 4K, and Airplay doesn't support discrete audio) and an Amazon Fire TV 4K (which doesn't have GPM available), so I assume I'll need a new device.

Another complicating factor at the moment is my receiver isn't 4K compatible (and this won't be replaced until the middle of the year), so I'd need to directly input the device into the TV; this means ideally I'd need to tuck the device behind the TV itself, rather than put it in the rack below (as no spare HDMI cables in the wall, damn it).

Does this mean a Chromecast Ultra is probably the main if not only option, given these specific needs and current limitations?

Any advice appreciated.