Currently, Hubitat's built-in ZW updater tool doesn't work with S2-paired devices (or some other scenarios). But for .ota and .gbl f/w files, this process here might help you avoid having to use a Z-stick to update...
So far, I've verified this works with ZOOZ gear (and these same basic steps work for Leviton), but I'll update the second post (below) in the future if other manufacturer's files are also confirmed to work.
For Zooz, I've just used the GBL file from the zip file, but I suspect the standalone GBL file they also offer would work too.
1.) Get the OTA or GBL file from the manufacturer.
2.) Next, install this updated fork of the original z-wave updater tool: [BETA] Updated binary firmware updater - 
Custom Apps and Drivers / Custom Drivers - Hubitat. Note: install this as a Driver (not an App)
3.) Next, add the firmware .ota or .gbl file to HE's own "File Manager" tool (found in the HE Settings area).
4.) Once loaded in File Manager, right-click over its name and use "copy link" to copy its local URL path. Paste that into Notepad or a similar basic text-editor app -- it'll look like this:
http://your.HE.ip.here/local/file-name.gbl
Now manually add ":8080" at the end of your IP, so it looks like this:
http://your.HE.ip.here:8080/local/file-name.gbl
5.) Go to the device's own Devices page in HE -- change the driver Type to "Z-Wave Firmware Updater" (that's the custom/user driver we installed in Step 2). Then hit "Save".
6.) In the new options at the top of the Device page, there'll be a "Clear Lock" option -- I recommend clicking that... I don't believe that can hurt anything, and it may in fact help a lot.
7.) In the "Update Firmware" option's entry line for binaryFirmwareUrl, copy/paste the 8080 version of the URL you made in step 4.
Click the "Update Firmware" button - the progress should be reflected in the Current States section over to the right. Progress may not be super fast, but it should be steady.
8.) When done, it'll just say "Complete device is flashing..." -- that actually means the update is finished.
9.) You can then swap the device's driver back to its regular driver. If you want to clear out the leftover update-related states on the right side, you can use the Device driver to do that. If you want to double-check the f/w updated for sure, you can use the Basic Z-Wave Tool driver to do that at any time too.
Good luck!
