You have options that work on the same lines. AirPlay Chromecast, Steam play, Nvidia Shield all just encode and decode video, tbh if we had one system the world would be a nicer place. But everyone has joined the band waggon and made each their own, not sure if its as licences cost, or some broadcasting laws? But if your looking for an AMD branded version kinda like the NVShield their isn't and wont be, it would likely be open source but with DX12 around the corner most of this stuff wont work.
Your best bet is to use Steam Share, just add explorer.exe to your game library then you can surf, play Origin games, load a floppy disk just for the hell of it. Buy a Steam box if you want something none PC, ARM based next to the TV. Seems like your best bet, youll get the same near perfect image to what NVidia, Apple, Google can give, just cant mix and match. Unless you go Green then you can still use your Steam Box