For the networking I found some repos with Nix and Gluetun (OCI containers). I don’t see them in my bookmarks, so it was probably a day project when I set up and didn’t keep the references.
That part is still in docker / podman. So any docker network guide just needs to be translated to nix.
The original used XI where it was 9 or 11 depending on the side.
edit: Nope I was wrong. That post links this one, lol.
https://infosec.pub/post/19153879