Or use something like Tailscale.com, secure private mesh vpn. No need to expose any ports.

Added feature that comes with it: https://tailscale.com/tailscale-ssh/

It’s also 100% free

I use Excalidraw or MermaidJS

Synology NAS + Tailscale

You can always use a Pi-Hole which offers DNS Hosting or if you have a Synology NAS

https://pi-hole.net/

https://dnssimple.com is also a great cheap solution that will host your own NS servers.