The Backrooms (from what I gather), don’t have that sort of ever-present danger except the rooms themselves (and the idea of what could be there, not exactly what is). And those are scary because they’re liminal spaces. That is THE primary driver of the fear (which I mentioned, cannot truly be replicated at HHN); the idea of what can exist in the emptiness. That means that any attempt at a Backrooms house is going to immediately have to work around the thing that makes The Backrooms works. If there are no visible (or extremely few) antagonistic creatures, the actual scares would be… victims looking around lost?