The term you would search for here is "split-horizon DNS". Assuming you're using a real domain name with hosts, you want a DNS server inside that resolves the LAN address, and the outside DNS server for everyone else resolves your WAN address (which presumably you reverse-proxy to inside host).

Even better is to not expose the service at all from the outside, use a VPN like Tailscale, and then use their MagicDNS service on the tailscale network to keep everything behind the firewall.

Every service you expose to the outside is more attack surface.