Calling it the Multiversal Link Canon
It's Really more a theory than a Canon though
Concept: In this version of the Backrooms there are at least 1 trillion People in the Backrooms which normally would be about 742 times more than people in the world and 14 more times than people who have ever been alive. Here, the Backrooms can be used as access tunnel between Universes. Even realities like Scp and Mha are accessable from the backrooms.