Propel ATL does not offer bike rentals, but here are some places that do!
Atlanta Bicycle Barn: Bike shop on the Eastside BeltLine trail that sells, rents, and repairs bikes
Aztec Cycles: Bike shop in Stone Mountain that sells, rents, and repairs bikes
Comet Trail Cycles: Adjacent to the Silver Comet multiuse trail
Pedego Atlanta: Offers e-bike and accessory rentals for full or half days; located on the Beltline in Glenwood Park
Tandem Mobility: in partnership with Town Center CID and Cumberland CID
Relay Bike Share by HOPR: Like you've seen in other cities, ride a bike for as long as you'd like and then lock up at any station.
Bike tours in Atlanta that may include bike rental