> you can use dnsmasq with Unbound

could you elaborate on that? How is the connection done?

Dnsmasq needs an upstream server to resolve the DNS queries. That upstream server can be anything, Google, Cloudflate, Quad9, or, a local Unbound instance.

You run an unbound server with a static IP, and point dnsmasq to said static IP.

OPs setup has this configured through Pi-hole. Look at the docker-compose file.

Edit: I just remembered Pi-hole has an official guide for this: https://docs.pi-hole.net/guides/dns/unbound/