#holesail is also pretty cool for punching service holes through NAT, although I don't think it's nixified anywhere yet.  Eould be a nice addition to #nix-bitcoin:  "electrs.holesail.enable = true;"

#headscale is an open source coordinator for a tailscale tailnet.   It's in nixpkgs. Limited compared to the closed source company coordinator, but good enough if metadata privacy is a concern.