If you're going the Docker router, I'd run separate Docker containers rather than an all-in-one. You get the same functionality, but you can route more than one app through the VPN.
Create a Gluetun container to use for the VPN, then have other containers configured to use the Gluetun container as their network.
All you need to do for the other containers is use network_mode: "service:gluetun" if you're using docker-compose, or --network=container:gluetun in the Docker command line otherwise.
https://github.com/qdm12/gluetun-wiki/blob/main/setup/connect-a-container-to-gluetun.md
Works great in Unraid especially, since the option to route a container's network through another container is available in the Unraid UI.