Every moment we make a decision we create a new universe.
It is not unfeasible to slant backwards or forewards (or even sideways)along the infinite possibilities of evey outcome of every moment.
The big question is - “is it quantum?” and the bigger question is “Does it matter?”
There’s little questions like "which set of dimesions?
the result:
Perhaps a singularity is required or perhaps not.
If not then there is no aparatus required.
The little questions being - are we talking about a gravitaional singularity or any singularity - it might even be a logical singularity like: “Honest?” or “Faith?” or the gap left by irrational numbers.
I don’t think for a moment that the big bang happened in only 3 1/2 dimentions.