Self-host templates without Caddy

I should have specified, I meant for IPv6. In my registrar I can add a record for fluxer.mydomain.tld so it points to my public IPv4, which is the same for fluxer or Nginx and the firewall will forward depending on the port. However for IPv6 I need to add 2 records for 2 different IPs since they're globally routable, aside from streams is there a way to deal with this that I don't know about?

I don't know a whole lot about ipv6 but I'm pretty sure you want your A and AAAA records to point to whatever is doing your ssl termination. You'd have to just redirect the ports from your nginx machine to the fluxer machine directly or incorporate an l4 proxy in front of nginx. This is getting a bit off topic though.