Which logically means your definition of GOD would include a non sentient physical processes that lacks a free will etc. At that point why label it GOD rather than say space time or whatever?
Existence of universe has nothing to do with something about universe. Or at leas not have to. You cannot explain existence of space time with space time
That’s one model, but we really don’t know what happened before the Big Bang.
Still labeling pre Big Bang as SpaceTimeTime or calling that Space Time and relabeling what we experience as local space time doesn’t really matter here. The point is our Big Bang could be happening infinite times in a multiverse without beginning or end. That’s one possibility where there isn’t anything conscious to point to as a GOD just the same kind of things which make up physical reality.