Many parts of Europe solved it in a more low-tech way: street-side parcel lockers unlocked with your phone. Massively reduces delivery cost (i.e., one driver can deliver far more packages per hour), is pretty convenient and safe (no packages left unattended), and best of all, doesn't require a fleet of UAVs.
You can pretty naturally extend this once you have self-driving vans.
I think Amazon has a proprietary version of this in some parts of the US, but at least where I live, the lockers are a car drive away, which defeats the purpose.
The last tower I worked in wasn't some really big tower (only about 16 stories) but in the lobby near the security booth there was a set of shelves operated by a food delivery company. Every day there would be a few restaurants listed, you'd place your order, and they'd deliver everyone's food around noon to the shelves. You'd just go down and grab your meal.
Seemed to work well enough for the times I used it. Honestly though I really valued the time to take a break and go for a walk and have lunch away from sitting at my desk.
Japan too, convenience stores are everywhere, packages go to lockers in the convenience store, unlock with phone app.
(Of course you can still choose to have them delivered to your door, but I find the delivery people don't ring the doorbell and then mark the delivery as missed, even with instructions to leave the package in front of the door. But that's a separate issue.)
The chinese too, afaik, in shanghai drones deliver parcels in specific parcel stations. Flying drones delivering stuff (through the windows?) to upper floors of buildings sounds like sth between scifi and madness right now. Having specific pickup locations solves a lot of problems like the ones here, as drones can just have to follow specific, predetermined routes that can be more easily monitored, instead of having to go to some random, different address.
You can pretty naturally extend this once you have self-driving vans.
I think Amazon has a proprietary version of this in some parts of the US, but at least where I live, the lockers are a car drive away, which defeats the purpose.