God is a common yet unclear term. One definition is “creator of universe”. We first must clarify what “universe” means. As far as I can tell, the traditional interpretation of universe is everything (i.e. class of all sets). In this case, the creator/cause of it (i.e. a larger class, which would hence make the universe a set) makes no sense.
Other common interpretations naively personify the God object as human-like, with notions of benevolence/morality. Others include concepts of omnipresence, omnipotence, and omniscience. I’m not really sure how to make use of terms like benevolence or omniscience, but I’d probably go with utilitarianism and omnipresence as respective equivalences. Now, any object with omnipotence and omnipresence=omniscience is at least as “big” (in the containment/causal sense) as the universe. But again, since the universe contains everything, by definition, then any object with these qualities is equal to the universe.
So it makes more to sense to “start” with the universe. Where one can possibly get by using this term is asking what caused variation/lack of uniformity in a hyperfluid with an initially uniform density and 0 velocity gradient. The universe could then be defined as the interval of nonuniform density/velocity of this fluids’ existence–spurred on by nothing more than some random perturbation.
As a theory, God is simply defined as an initial object in the category of events. As an initial object it can explain any arbitrary thing, and this is precisely the problem. Science strives to find a necessary and sufficient theory such that the universe (the set of observable events) models that theory. While God is clearly a sufficient theory, there is no reason to suggest it is necessary.