i was also shocked when i saw the size of his room, let's remember that it's not the same exact story with mc so things can change. maybe they drew it to be like one of the rooms in his house? imagine to have the cars on the ground floor and then that room, the kitchen and the bathroom or whatever rooms you want on the first floor. i'm just speculating tho
I can understand that but the computers where he hacks is right by a window which doesn't make sense since in the game he lives in a high security closed off place. Anyone could break the window in his place it's not safe. Seven in the game is extremely concerned with secrecy and safety but this just looks like a normal place.
Sevens apartment being small and also above ground kind of doesn't make sense? He's rich(property wise) so he invested in a bunker for safety purposes and also he could store his tons of cars. But I guess maybe they went for a more realistic approach?