The Fallacy of the First Cause.
“Cause” and “effect” are phenomena which are observed within the Universe among already existing entities. We never see cause and effect creating new entities. Indeed, the premise/fact that energy can neither be created nor destroyed implies this.
The initial conditions of the Universe (if such an idea is ontologically meaningful) can be the uncaused cause and don’t subsequently require a causal explanation. To argue that the existence or creation of those initial conditions is a form of fallacious reasoning and begs the question.
The principle that something cannot come from nothing means that [the theistic] God is not necessary. If we give up that principle, then [the theistic] God is not necessary.