One thing that I routinely did with my previous router setup (which admittedly was a Linux machine with two NICs) is run local DNS. Since dnsmasq works nicely for DHCP, it would populate the local DNS entries for any hosts that got an address, and things I manually added to /etc/hosts, and since it announced itself via DHCP replies as the local name server I could easily add shortcuts which were usable by all the clients on the network. This also comes in handy for being able to login to the gateway machine and then SSH to something internally, or from one internal host to another, since you never have to know their IP - the DNS server just knows and does it.
My request then is for some kind of "local DNS" in the eero that does just that - gives out A records for hosts on the network, does PTR records so that 'last' on a host knows where they came from nicely instead of just an internal IP (yes I know that dynamic hosts could cause that to change), and even allows for other things to be added so I can have the short name 'foo' point to a machine at work for example and not have to refer to it as foo.subdomain.work.edu (and yes I know I could do that locally, but I'd have to do it for every host instead of having the local DNS do the lookup for me and change it in one place).
In this example, give this macaddr any IP, but A-rec and PTR-rec that IP with the name "Fred". There are other command options for basic PTR/A/AAAA management and CNAMEs as well.