You are absolutely right, they do have individual power switches. All of them are on. And I even tried to take the plug for AMPCD out, and plug one of the DDIs into it. It still wont discover the DDIs, and if I plug my AMPCD into one of the other ports it still sees my AMPCD.
As for the backlight, when I go into SimApp, it only shows me the AMPCD. It refuses to show me either of my DDIs (both under "Devices" and "Keybinds"). From which I gather that something is going on with my DDIs that is preventing SimApp from seeing them. Even just now, I am trying the following chain PC > Hub > Left DDI is the only thing plugged into the Hub in the same place where AMPCD was plugged in and working.
DDI lights up, but is still not being discovered either by SimApp or by Windows as a plugged in USB device.
Thank you so much for trying me to help out with this as I have very little experience with all this hardware.
The Hub that I am running is https://a.co/d/dto4NmN
If there is a better one of one you know of that works with 14+ USB ports I am more than willing to try.