PortNull

Yep. I had it set up in a docker compose setup with tailscale and gluetun. There is actually decent documentation for this on gluetun docs i think.

Then your tailscale container exists via gluetun which connects to your VPN.

Edit: Found these

https://unix.stackexchange.com/questions/786512/how-to-enable-direct-connection-to-tailscales-exit-node-with-gluetun

https://lemmy.world/post/7281194

Yes. Run a tailscale exit node which connects to the internet via said VPN. Connect to tailscale on android and select the exit node

Now you are routing android to tailscale and exiting via the vpn.

Not sure about pangolin on this front

Navidrome server.

Mobile: dsub2000

Desktop: feishin (or sometimes my own tui client)