I see our expanding universe as a tiny part of an infinite greater universe. Our tiny part or arena is expanding, and there were preconditions to the expansion, i.e. a "before" the big bang. We expand in to the greater universe until the energy density of our expanding "ball" is equalized with the energy density of the greater universe.
By that time, within our expanding arena some interesting things have occurred. The preconditions that lead to the "big bang" are part of a process of "energy to matter to energy" that defeats entropy and so those interesting things I think happen during the expansion are a part of the endless change that goes on in the greater universe.
In this scenario, our expanding arena has a center while the greater universe has no center.
We can't detect the center of our expansion because everything is moving away from everything else due to the energy density equalization that occurs across the entire expansion of our arena, not just at the expanding surface.
And there is the timing of matter formation in the arena. Expansion went on for some time before matter formed from the energy ball that emerged from the "preconditions" (a big crunch).
I guess everybody has a scenario
.