If there is, or is not, an omnipotent being who is independent of space and time, what any human claims to true or false, is irrelevant.Except there are some Christians who claim that Jesus or Christ (I'm not sure how distinguished they are) was the Word that was there in the beginning. "Elohim" was plural because the Trinity always existed in one form or another. It's a mystery.It's a fallacy on its face. "God doesn't exist if Jesus didn't exist" proposes that a previous event is dependent on a later event.
Okay.Jesus could be the Messiah, a charlatan, or just an ordinary man, who lived sometime before the calendar was rearranged in his memory. Whether he was any of these things or none of them, cannot determine whether or not God exists.
Humans are prone to make mistakes and it's easy to demonstrate that humans are frequently wrong. Finding a paradox or a contradiction in another human's logic and thinking, has no bearing on whether something which cannot be perceived with our ordinary senses, exists or doesn't.