There is a large rental center but it is on the outskirts of the airport.
If you are at the International terminal you get a shuttle round to the domestic terminal and from there you can get the skytrain to the rental center.
https://martaguide.com/things-to-know-a ... -skytrain/I will be doing it in February and we have a room at the Marriott Gateway on the first night which is the first stop on the skytrain so in the morning we just jump back on it for a short ride to the rental center.
I haven't done it this way yet, but two years ago I did return a car there and it's a very short shuttle bus ride to the international terminal.
Dick D