I've got a similar setup myself, check out https://lobste.rs/s/yppnts/tailscale_on_nixos_new_minecraft_... where I describe how I did it. It's quite custom but all open source. https://github.com/infinisil/on-demand-minecraft is the main part
Part of my idea was an actual web home for the server (leaderboard, map, etc.) so if we play MC again I will see if that is possible with your project.