External DHCP Server

As a sysadmin in training, I am trying to teach myself about some tools, like network booting with a pxe server by experimenting on my home network.

Unfortunately, it is my understanding, that the only way to disable the built-in DHCP server is by switching the Eero routers into bridge mode, and then setting up some external device to handle routing, which is a bit far for my needs.

I would like to disable and setup an external DHCP server, whilst leaving most of the other features of the router enabled.