Just updated my core, desktop, etc. to Roon 2.0, and then downloaded Roon ARC to my cell phone. I next opened the desktop application to configure Settings>Roon ARC. Before this connected, I had to open the following firewall port in UFW on Ubuntu box:
sudo ufw allow 40229/tcp comment roonarc
I then cut wifi on my phone and guess what, I’m streaming!
Roon, please add Roon Arc to the Microsoft Store!