I normally rent with Hertz (high status) and not had issues. I used to rent with Alamo, but they charge up front, not when you return. So when traveling for work, I would get the charge on the first day, but did not reimbursed until after the trip, so sometimes had a long rental I had to pay out of pocket.
I did have a run in with Enterprise. I went to T41 to get some transition training and pick up my airplane. I flew into IAH and Ubered to hotel. Next morning, went to Enterprise and rented. My transition IP told me about the FBO desk, and we called and arranged to leave the car at the FBO. I get home and get an email that Enterprise charged me $200 to pick up the car.
I called and explained that the FBO drop off was coordinated, at no cost, with the FBO desk. FYI, the FBO was maybe 4 - 5 miles from the rental office. The lady said I should have come to the office to drop off the car and they would have driven me back for free. I pointed out I left on Sunday. So she tells me, we would have reimbursed you for an Uber back. Really, maybe tell people that. I pointed out that she would cut the fee in half and asked if that would be acceptable. I said sure, and I will NEVER rent from Enterprise again. She decided to waive the fee.
The no cars thing should be getting straightened out. Over COVID, few rentals, so they sold their cars but did not reorder. Then people start traveling, but supplies of cars are low and slow coming, so lack of cars. Eventually, things will even out.
We rented from Alamo at SAT last spring. Arrived and NO cars. Had to wait about 15 minutes for a car to come in and be cleaned. But they did clean it before turning it over.