Rent a bitch a horse, she will ride for a day, buy a bitch a horse she will ride you everyday - Margaret Thatcher.

If you are only accessing the services while connected to tailscale using the tailscale admin console you can add a nameserver, and then point that to a local DNS resolver. The local resolver can point the URL you want to the IP with the ports you want. I don’t know if Synology has DNS resolving apps but that might be an option, otherwise you could run pihole or something similar to achieve this.

Good shout, get some metal hangers too as a backup.