About a man with a career and a forbidden room

It’s about a movie in what I though was post-apocalyptic setting. Food was hard to come by. And the protagonist lives in his home in a city. He does not trust anyone.

He took up a career as a security I think. And there was this forbidden room that the boss forbid him to enter. There was also this red-haired woman related to the boss, (probably adopted), and they kind of attracted to each other but somewhat that made it a dangerous situation. I thought the boss kind of looked like Laurence Fishburne and the protagonist looked like Jim Sturgess, but nothing come up.

In one of the scene, the protagonist defended his home from enemies attack.

Found the movie name. It was The Last Man (2018).