When I plan to use a rental car I usually pack a phone holder that fits on air vents. You never know if you’ll be able to connect your phone to the car so that’s a small backup.
Be sure to let them know at the rental corner if you are dissatisfied because it doesn't work with your phone. Run car companies buy a lot of cars and in turn actually have input to how a car is made and they also have reason to care about your satisfaction. rental cars is one of the best places to get things to change because the rental car companies can get a change that you alone otherwise couldn't get made.