I wrote a long response but it disappeared. Unless things have changed since Aug 2023 you can drop your car in T1. I had Avis but I saw all the majors had marked spaces in there. As soon as you enter T1 there are counters for the majors where you can drop your keys. It's right across from the terminal where the taxis drop off. Maybe P1 or P2. Follow the signs to car rental drop. Avoid the minute depose' entry and I think you have to go through a gate that will open automatically and you continue in a lane parallel to the minute entry, and then there is a ramp up to this parking area.

Let me know if you want more details.