Sorry I was typing on the phone so too brief.
Roon can access networked DACs using either Apple Airplay or Roon's own protocol called RAAT. Volumio which came pre-installed on the Pi that was included on Katana only supports Airplay. Using that, I had no problem playing music using Roon to Volumio and Katana. The issue here was that for measurement purposes I need to have a bit-perfect, 24-bit audio pipeline which airplay does NOT support.
Other Pi OS packages do support RAAT. I just have not had good luck installing them and getting them to work.