if its just a few friends maybe use tailscale? put it on the server, then have your friends run it so their on the same network. then use tailscale internal IP’s and dont worry about DMZ or port forwarding?
Im running mine on unraid but as they mentioned, Just make a VM in unraid and install AMP on that. Linux/ubuntu is recommended. Works well! (I went with windows server because space engineers is my main gig but there are caveats to using windows)