I think such a thing is difficult to comprehend except maybe mathematically. We are our universe and our universe is us.
I think when you are trying to envision the universe being contained in anything, you are already on the wrong path.
Maybe akin so asking: "What came before time?". The question itself is a contradiction.
Why is that the wrong path? I think these are valid questions. Please, I’m curious to hear your thoughts.
It’s a meaningless question to ask because the universe (according to the typical definition) encompasses all of space and time. It does not make sense to ask what came before/after it, and it does not make sense to ask what is outside the universe.