It sounds like the devices are too far from the hub when your pairing them. That’s why you get the generic Zwave device. Try pairing them right next to the hub or move the hub right next to the devices and move it back after. You may also need a repeater between them that is powered all the time and not battery operated. Try a Zwave plug or something similar, you may need more than one depending on what else you have on your network!
Yes, they are repeaters and they also have S2 security so you may not need the plugs. Try and pair each one right next to the hub like I mentioned earlier. Also make sure you work out away from the hub. So, pair the one closest to the hub and keep moving to the next one.