Parallel worlds shuttle door

Gu Ning struggled to survive in the post-apocalyptic world, trying her best to protect her parents and her loved ones, but was tragically designed to die in the streets.
She woke up in a strange space.
A space, a door.
The door opens once to peace, and again to the end times.
She travels between the peace and the post-apocalyptic world, collects the wealth that people do not value in the post-apocalyptic world, goes to the peace world to exchange food and equipment, and returns to the post-apocalyptic world to save humanity.