Yup, if we're in a simulation pretty much all bets are off. Mandela Effect could merely be update patches. It could patch a proof that our world is not a simulation.
Let’s assume it’s simulations all the way down and we exist in plane P=n. The question is are we at n=0.
Looks like this result says we can’t simulate our plane in a computer. But the stuff in that simulation exists in P=n+1. So maybe the conclusion is “you can’t simulate n from within n+1” which means we can’t simulate our own plane, let alone our potential parent, and doesn’t mean we don’t have one