Hitch bike racks mount onto a trailer hitch receiver. There are currently not any trailer hitch receivers available for your 2021 Mercedes Benz GLA so you will want to go with a trunk-mounted bike rack instead. This is usually a cheaper and easier route anyways.
I recommend looking into Yakima FullBack 2 Bike Rack - Trunk Mount - Adjustable Arms # Y02634. This attaches to the trunk of your vehicle and allows you to safely hang 2 bikes on the bike rack. The points of the rack that make... view full answer...