Hi marya in my experience wrapping my cuttings in a plastic bag helps a lot because the moisture stays constant
but there’s one thing I learned the hard way: don’t ever put those in direct sun because it’ll cook the plants
I lost a batch of fittonia that way
I think it turned the bag into a greenhouse or something
but when i was careful it definitely sped the cuttings up alot, nearly twice as fast compared to the open-air ones
maybe for ZZ plant won’t speed up by as much, but it should still work well