I am curious. I was planning out something and didn’t know how to deal with lack of USB ports:
If I only have 2 USB ports, and don’t want the USB stick that combines Zigbee and Z-Wave because I hear it’s not really Z-Wave Plus, what can be done? A USB hub wouldn’t work would it? Wasn’t sure if the ports would be detected or if the whole hub would be seen as one port.
I know people are using USB hubs with Aeotec ZWave sticks on RPi 4’s because they won’t work when directly plugged into the RPi so I’m going to guess that you’d be OK. It’s only a guess though!
USB hubs have been around for as long as USB. They work as you’d expect, because it’s designed that way 
Plug one in, powered or unpowered (if you’re on a Pi I’d recommend powered) and plug your devices in. It will work.
I use a USB hub with 7 ports for Zigbee stick, an RFXtrx433XL, a Aeotec ZWave and a SSD disk (from which I boot the RPI) it works fine. Each device is recognized independently just as if you had additional ports. The hub I use is Plexgear Desktop 710 USB 3.0-hub. The USB sticks sometimes need external power to work properly, so an externally powered USB hub is a good idea.