I think that is exactly what they are, Joe. They amplify the signal to cover the space. The setup I have works well. There are a couple of TVs in the house that are WiFi and distant from either WiFi signal source but work fine. The mesh setup is newer version of this system since I put in my device to extend my WiFi signal.

I took a look at an old HD that was for storage; they come with extra software so they can be used for more than one computer, but I don't need that. (And the old drive is tiny by today's standards - just 2Tb.)

I think I probably have enough gear here, if I get the adapter, to set this up to serve as a backup for the desktop computer. My laptop serves as a spare, a backup if something happens to the big one, and on several occasions I've been able to keep working during outages while using my phone as a hotspot for the laptop. I can save anything from that into the MS OneDrive to grab later from the big computer. (I have a tablet that could approximate some of the laptop work, but they're not really great for complex tasks.)