Resolving internal names/set default dns domain?

How does Eero provide internal DNS resolution?  I'm using my gateway eero as a default dns server, but it's not passing a DNS suffix through DHCP, so merely pinging machines on my internal network by name isn't working.  I can (obviously) look up the name on the eero app and then ping/access it by IP, but how do I go about setting eero to provide a suffix?  I'd like all internal machines to be <hostname>.local or <hostname>.house.local or whatever, really.  But looking up NAS boxes and linux servers by IP feels very 1983...