None of the vehicles have a built in mount. A small percentage of vehicles don't have Bluetooth. The smaller the vehicle, the higher the percentage. Most people use a ventclip or windshield mount. Some vehicles, usually larger, have integrated navigation that don't need the phone.
No cars have a dedicated cell phone holder. Some have Android Auto and Car Play support. As suggested by Martin, grab a cheap removable mount that will not cause damage to the vehicle.
Same experience here as well. My advice: get a magnetic holder you can easily transfer from car to car. They cost about 7 bucks.
I have not had a car with a dedicated cell phone holder. They do support blue tooth,usb, and Android auto in all the cars I have rented.
Call and reserve a car that has equipment you need. They are very accommodating and will try to meet your needs.
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