Hi @DeaconBlues,
Android does not support multi-channel output at this time. I think your best bet here might be to use the NUC’s HDMI port to stream multi-channel to the AVR, but if you are thinking of using a seperate endpoint to do this, you can take a look over this threa (Is there an Roon endpoint that supports multichannel?) where users discuss multi-channel Roon endpoints.
Thanks,
Noris