Assigning hostnames for devices on home network

I have a home network with ~35-40 devices. I would like to be able to assign my own hostnames to all of them. Doing so on my router (Asus RT-AX55) does not appear to be sufficient -- I have my own naming scheme assigned to my devices there, but attempting to address them from my Mac via commonly used methods in the Terminal (e.g., ping or dig) does not work... Network Radar does not find DNS names for any devices, and so on.

After having spent the past few months attempting to address the problem with Pi-Hole on Ubuntu, I am now ready to write off Pi-Hole. I would also very strongly prefer not to attempt another Linux solution, either. I'd be interested in hearing how others have addressed this problem, especially inasmuch as it seems like solving it should be trivial... just about anything else I've ever wanted to do with my light bulbs and hubs and contact sensors and what have you has been pretty straightforward, but this has proven intractable for quite a while now.