Roon on Android cell phone on LTE/3G via VPN

There was a thread like this long ago but no more replies are allowed:

I discovered some “progress” - when on LTE but with VPN to home, Roon app on Android connects successfully to Roon core at home but it is not possible to play anything - the app doesn’t see the phone, but surprisingly it sees devices at home and I can play to them.

When on WiFi, in the app I can select “This Phone”. When on LTE and VPNed to the home network “This Phone” is not available.

Can you please let us use Roon on cell networks via VPN? Sometimes I’d like to do that but have to find other options. Why not? It’s 2022.