That's not the way it work, YoursTrue.
Every galaxies and stars, including our star system, with Earth, including life on earth, only exist in this universe.
That's where all the evidence lies.
There are no evidence that any can exist outside of the universe, not even space and time. And we have only technology to observe the OBSERVABLE UNIVERSE.
Anything existing "outside of the universe" is pure conjectures, and most likely something you can never test & verify, and therefore can never "know".
Anyone can make up all sort if claims, and lot of these claims cannot be verified, and "knowing" & "knowledge", requires evidence.
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Believing isn't the same as knowing. Knowing requires verification, believing don't.
If you believe in concept that there are something beyond this universe, that "existence" can exist "outside of the universe", then by all mean, show evidence toI support your claim/belief, because the burden of proof would be upon you.