In Texas they have a lot of houses with what amount to two living rooms. Here I refer to the large one as the den and the second one as the front room.

The device in the den is plugged into a LAN port in the wall but serves as a wireless boost and a LAN site (I have the streaming Fire stick and the Blueray player wired for streaming TV and things like Netflix plugged into it). There is room there for one more wired device. It's a Netgear device to extend WiFi signal with the bonus of the functionality of a 4-port switch.

Talking it out here and making myself go through the baskets of cables and peripherals has been helpful. Thanks! (I looked up "using Western Digital external drive as NAS" and it came back that they have some meant for that, and I remember that I bought some for that that I used in a different way. Too small now to put them to the original use, but I'll look at the specs on this new one and see what's up.