Please forgive me if you have rented cars at other places, just not at Disney. I am guessing this is a first time rental.
Rental cars can be tricky. There are lots of pitfalls with rentals. I've been renting for 50 years and still am wary each time I am at that counter. As a first timer, I would recommend you do the following:
If you have AAA, that is your best bet. Call the number on your card and talk to a
travel agent. You want them to be available should you run into an issue with the car, rental counter etc. If you don't have AAA, it is under $100 a year and gives you other savings and protection. They will likely help you get a name brand rental. Ask if all the household members can drive without extra costs.
Go online and get a loyalty card through the rental agency you are going with. They may treat you better. It gives you another avenue should things go sideways. You may get perks like an upgrade.
Call your auto insurance company to see how they handle an accident when you are renting so you can say NO when they try to overcharge you for insurance you already have. If you do not have a car at home or adequate insurance taking the car insurance from the rental company may be warranted. Bring a copy of your insurance policy (proof) with you.
Call your credit card company to see what coverage they offer if you have an accident. Obviously, you have to use that card for the rental. That also allows to file a claim should you be overcharged. I was charged for a car I never rented back in 2022 since there were car shortages then. I had saved a copy of the chat to cancel that car which saved me! I had to fight through my credit card to get the money back but I won. See below.
Do not pay in advance. Pay at the counter.
Ask about getting a full tank at pick up vs topping off on the way to the airport. Some agencies want you to show a receipt to prove you bought gas within a few miles of the airport. I always get a full tank and forget about it.
Don't let the counter people con you into a bigger car for more money. It likely means they do not have the size car you reserved and they are trying to get YOU to pay for the fact they have to give you the next size vehicle. The counter people are persistent so I hope you can say no. There are fewer small cars so you may get an upgrade with a small car reservation.
Inspect the car you are renting and take photos. If there is any damage to the car like windshield, dents, scratches go get someone to document them. If the interior smells like cigarettes do the same. You do not to be charged for something you did not do. Don't feel bad asking for another car in the same category.
Just a few things to consider with a rental car. We get one 95% of the time as we like the convenience. Good luck!