Indeed. A fallacious argument. Even if it could be shown the universe/multiverse had a cause, not convinced ‘god did it’ could then be reasonably inferred. Just as so far, ‘god did it’ has never actually been proved, on any claim.
During the 1970’s such claims were arse deep in popular reading.Same reasoning, except 'god did it ’ was replaced by ‘aliens did it’. Those books were so popular that they had their own genre.