What I’ve usually seen is that the VPS does TLS termination and then comms between the VPS and the LAN are sent http, but still secure due to traveling through the VPN. This is the easiest way if you don’t require full e2ee and trust your LAN

Final Fantasy XI is still a beautiful game and is self hostable, but as with most MMORPGs, you need lots of people to get the full experience. Luckily if you’re hosting your own, you can always mod settings to make yourself lvl 99, turn off enemy AI, teleport anywhere, or whatever.