Unfortunately it seems that zbackup has been largely abandoned. Too bad
as it is a relatively interesting concept, and if you avoid using "gc"
then it is pretty solid.
I've moved to restic nearly across the board, with one specific case
where I really need zbackup's amazing deduplication.
You might also want to dig into
https://attic-backup.org/ although I
admit I'm not running it and therefore cannot comment directly. Having
the possibility to run directly from Windows was worth the downsides of
restic for my current purposes.