You're getting into omniverse territory here, I think. But if accurate, then the dimensions without multiverses just lack the ability to perceive, observe, understand, measure, prove, or travel outside of their own universes. There's a whole multiverse of such isolated bubbles that will "know" that there's no multiverse, and we have a 50/50 chance of being in one.

Or, the conjecture of the multiverse, being non falsifiable, makes it as scientific as the boogie man or the tooth fairy. God of the gaps anyone?

One night I was thinking about multiverse stuff and I wondered if you could cause a paradox in another timeline. I got stuck on thinking that it might not immediately destroy the timeline and then I began to worry what it would be like if we lived there. (I was not sober lol.)

Group theory already solved that one 😄