Indeed, we've been planning to screen in our front porch for a while just so we have some security when opening the front door while the cats are on that side of the house.

It would also provide some security by obscurity for any packages we get; according to UPS, right now I've got three packages totaling about $500 of equipment sitting on my front porch in plain view to anyone going past the house. Thankfully the house sits nearly half an acre off the main road, with no sidewalk and in a semi-rural area. Still, Murphy's law dictates that today will be the first time I have a package stolen. I'll find out when I get home in a few hours, I guess.

(My regular UPS guy normally doesn't deliver to me until after 6pm, he knows my schedule and it lines up well with his driving route most of the time. I'm guessing this is a new driver, or else a really light day for my regular guy.)

Lots of apartments already have airlocks.

Very similar to an airlock

Lots of options.

My apartment and several in the area, have a concierge, and they’ll act as a “porch” and even deliver it to your door later in the day

Some apartments have mail rooms, some with automated entry based on if you have a package or not

It’s largely a solved problem

A standard little lobby where people leave their shoes and whatnot, except normally the inner door doesn't have its own lock.

For apartments, amazon has a different approach. https://thehub.amazon.com/home