The following is not accurate
There are many interpretations and paradoxs, everything is still a theory.
Its is said that if a atom is locked in a impenetrable box , in quantum world,
There is still a probability of finding it outside the box.
Many world interpretation is just like that .
It states every quantum outcome, can be observed somewhere ,
Let me say about wavefunction collapse, it is a thing that occurs when a atom which is present in more than one state or place , when observed , collapses the whole system.
Though this sounds practical, studies suggest that there will be no wavefunction collapse, that means many world interpretation is possible.
If the universe is infinity, ignoring dark matter, then multiverse can be possible.