I remember the phrase “existence is not a predicate” and that logically since something exists there is no question of causation for that requires an action to effect another action and mere existence is not an action. But cars do exist as the result of manufacture we students replied. We were speaking of the existence of the universe, however, the existence of all.
God’s creation is not your human scale creation.
Even the most medieval monastic monks had some ready answers. The sum total of all or The ALL exists but cannot be the result of something else except as a result of itself for the ALL must include all causes and results of causation by definition of it being the ALL. There are no causes left over, so to speak. God did not “cause” the universe to “be”: there was no action before god created it and therefore no causes either.