Such buildings allow for great efficiency (it probably has its own stop on some kind of rail transit and still a reasonable cost of living) and that includes pizza delivery. Imagine delivering multiple orders a minute. The salary (and tips, even outside the US) would be great. They will probably even allow you to call the elevator with an app before you walk to it for extra speed.
I have in-laws living in China, and honestly - it’s a lot easier to navigate those sorts of high rises than you might think.
Most residential buildings I’ve visited have lots of dedicated lifts, so only 2 apartments per floor share one lift. So you would only need to provide something like: Tower 37, Floor 19, Apartment 2.
The Chinese love their delivery apps, too - their drivers (technically scooter riders) are very used to this.
Now the city of Chongqing is a whole seperate matter, that place is an M. C. Escher drawing in real life!
There's a good chance that apartment building has easy to find organized unit numbers that pizza delivery guy can understand. Building may even have multiple front entrances each with distinct addresses.
Do they generally bring it to your door?
Where I live they just call you that they're waiting outside and wait for you to come pick it up. Same goes for delivery drivers. Sometimes they don't even leave the car.