you may want to consider voting for this feature request, in the hope that GOG would add cloud sync support:
You can create your own cloud saves by using a cloud storage tool (I use Dropbox). It's not as convenient as Gog providing the cloud support themselves... so I still recommend voting for the feature... but it works with a little effort. You copy the savegames (or the save game folder) to a Dropbox folder. Then create a symbolic link in Windows using the console command "mklink" (use /D option for entire folders). Be sure to use mklink to link to the same files or folders in Dropbox on any other systems you are playing the game on.
I have a laptop and a GPD Win that I play my games on... and this works like a charm! I've been playing some of the old Ultima games this way... and I can switch back and forth easily between both systems and continue playing where I left off. The catch for individual files, is that you can't link them if they don't exist. So you might need to save a game in each slot to make the files appear and then link them. I haven't tried this for Jazz Jackrabbit yet... but I will be trying it soon.