You are using them wrongly, almost certainly because you don't understand how they work and are installing them in the wrong locations. They work best in small rooms, usually you'd either have a number of them to cover the whole house/apartment or only keep them in "cool" rooms where you'd go specifically to cool down, like your bedroom.

Secondly, AC units do not create a vacuum. Even if they did, houses are not air tight spaces, there are gaps underneath your door and cracks in your window, almost certainly there are cracks in the cover for the window. AC units work by circulating air through a condenser that sucks the heat out and moves it outdoors, that's why the back is constantly dripping water: its accumulating moisture from the outside air, since the back of the unit is just a giant heat sink.

As for the noise, nothing you can do about that. Most Americans are used to it and find it comforting since summer nights in the US can get very hot and these units are often run through the night to help people keep cool while they sleep, often from the youngest age. If you didn't grow up with them then you're probably going to hate it either way.