It seems to me that the concept of Backrooms could be applied to Alice's Wonderland and to the Underground in Jordan Peele's "Us". I have the same feeling in regards of The Lodge, or "Another Place", in Twin Peaks. All these places in fantastic fiction share the oddity, the uncanniness, of being composed of pretty common elements, such as corridors, gardens, hallways, curtains, and yet carrying an unsettling ominous atmosphere. There is some eeriness here that also reminds me of the Silent Hill franchise, or specially Silent Hill 2 due to how Pyramid Head behaves narratively, standing as an antagonist the chases you throughout the whole game. Could it be that Silent Hill is a whole town inside some unknown Backroom level? Could it be the case of the main character in "Jacob's Ladder" as well?
That's some food for thought.