AThinking outside the box…
Use the Gamestream feature in your Nvidia Shield to pipe the Roon Ui on any computer on your network with Roon installed (used as a controller) to your main TV in the listening room?
Its what I’ve done to my delight. 
Not installed directly on my shield, but using its Gamestream facility to have Roon UI up there on my 65” OLED controlled by wireless keyboard connected to the Shield.
Audio wise it helps (I guess) that my dac is a Roon Endpoint and I just select that as my output device, can do thwt from any Roon controller connected to your Lan.
Pics here: