proof is a justified true belief. X and X2 can yes be repeated, then you are just ‘begging the question’ of reasoning poorly or justified, and assuming an argument. Objectively certain belief is impossible to conceive of as being false. Adequacy ruling out luck and accident elucidates subjective, and objective states that is the link to knowledge. A justified true belief S knows & q is true & S is justified in believing that q.godelian,
So, yes you are correct 'begging the answer become subjective a sort of feeling that one cannot possibly be wrong. Possible: S knows that q if and only if S believes it is possible that q. Possibility is a dangerous and not necessary.
An atheist needs to also prove non-existence of God, which the Bible Proves: Argument, Fables, and law, literature, and mythology, etc through arguments.