@Bucket I've not personally used any, but heard of a few outfits via the CoS: https://www.cityofsydney.nsw.gov.au/transport-parking/rent-ebike-green-square-free (Zoomo, Jot, Lug & Carrie, and Sydney Ebike Rentals.)
They generally do monthly rental/leases, which is a great way to try it out for long enough to actually find the good routes to your places. (Which often takes some trial and error in Sydney!)