More importantly, most drones cannot physically adjust the tilt of the rotor blades (which is called collective pitch control in helicopters). Helicopter autorotation requires rotors with a lot of angular momentum and usually an abrupt change in the collective pitch right before landing to turn that momentum into thrust and slow the helicopter down.

There are RC aircraft with collective pitch controls, like most RC helicopters and even some multirotors. These RC aircraft generally can autorotate, as well as do things that are probably not practical for full-scale aircraft to do, like fly upside down. :)

A collective pitch quadcopter flying upside down: https://youtu.be/MVL_Hf4ilLg?t=162

An RC helicopter doing, well, all sorts of acrobatics that hardly make sense: https://youtu.be/KmPchrGW1TQ?t=48

An RC helicopter autorotating: https://youtu.be/bxQ5kwqiPN4?t=136 (this one has an internal combustion engine, although that shouldn't make much of a difference for autorotation)