Well, @gtunes and anyone else interested…
I got it figured out - was some blood sweat and tears, but now that I have Aaron Turner’s amazing udp-proxy-2020 running in a container on my Unifi UDM Pro and passing port 9003 UDP packets to my phone and back, I can activate Teleport (ahem, Wireguard cough cough) on my phone over cellular, and use the Roon Remote, um, remotely. Which isn’t what I set out to do - I’m still trying to get my two homes to work as a single home with a single core when I can get UDP packets to go back and forth over my site-to-site OpenVPN tunnel, but as a side effect it is very cool. Except for storing music locally on my phone, I actually think I might like this solution better than ARC - though as you point out we’ll see if Teleport is stable enough. Anyways, that wasn’t my goal but it’s a nice side effect. And I relearned vi and used docker / podman for the first time.