@otinkyad I scored a NUC10i7FNH on eBay for a deal and got it setup over the weekend.
I did a fresh install of ROCK on the NUC and then restored my latest Roon backup.
I can confirm the HDMI output shows up as an endpoint (along with the analog out) without issue. Thanks for your help @otinkyad and @Enrico_Castagnetti.
Hopefully this thread will help others.