My grandparents drive slowly at night, but they still prefer adaptive and HID/LED headlights, as these add-ons can only help and their SUV is fitted with them. Presume that the rental car companies' HID/LED headlights are legal.
They've found that rental cars' halogen high beams aren't adaptive and are too dim, as substantiated by the Insurance Institute for Highway Safety (IIHS) on Nov 29 2018:
Just over half of 2018 model vehicles IIHS evaluated are available with headlights that do an adequate job of lighting the road at night and limiting glare for oncoming drivers, but most good-rated headlights are optional or bundled with features that can raise the price of the vehicle.
"Consumers shouldn't have to buy a fully loaded vehicle to get the headlights they need to safely drive at night," says David Aylor, manager of active safety testing at IIHS. "All new vehicles should come with good headlights."
Avis's and Enterprise's executive relations manager said that because stocks change, specific models can't be guaranteed. Hertz can guarantee a model, but not one with adaptive HID/LED-headlights. The best they can do, is to save one for my grandparents if one happens to be on their lot.