This device can be difficult to include. Did you get a pop-up asking you to enter the last few digits of the DSK? If so, your controller recognized that it wants to talk S2. But in my experience, this device in particular has a very short timeout for that step. If you’re doing classic inclusion, you really have to have those last few digits copied to your clipboard, ready to paste in and hit “Next” as soon as the dialog pops up.
Luckily, things have improved, and ZWaveJS now support Smart Start. That’s by far the easiest way to get this device to include correctly. In ZWaveJS UI, go to the Smart Start tab, and add a new entry by scanning the QR code on the back (click the plus in the bottom-right corner of the Smart Start tab, then the QR-code looking option). You might want to do it on your phone – I’ve found computer webcams can have a hard time scanning those tiny little QR codes.
Once the entry is added, exclude the keypad, unplug it from power, and plug it back in. It should automatically join your network in a minute or two. If you don’t see that happen, you might need to fully factory reset it, which just requires holding down the reset button for 10 seconds until the green light on the front flashes. Then unplug it and plug it back in.
As far as node numbering gaps, don’t worry about it. Things can get a little wonky if the main controller isn’t node 1, but even that isn’t actually required. Everything else is just aesthetics. To force the controller to “fill in” the gap, you’d need to add and remove a device ~220 times, until the numbering wraps around.