Proof that God doesn't exist

[Edwardo Piet]

If the entire Bible is allegory then how can we determine there was even an historical Jesus?

I'm not saying we can. But that doesn't mean there wasn't one. Absence of evidence for the existence of something is not proof of non-existence. You still haven't disproved it. Are you simply trying to make a convincing argument or actually trying to disprove Christianity? Because the OP seems to suggest that you think you are disproving Christianity.

I believe that some forms of Christianity may be able to be disproved, but not all, and that is what I am trying to demonstrate.

There would be no way of telling what is real about Jesus because he's obviously so intertwined with everything else that's allegorical in the NT.

Irrelevant. You are giving good reasons to believe that it's all nonsense, you're not disproving it.

I was trying to disprove it as a whole, but it seems like everytime you turn up the "allegory knob" and change the allegory content closer to 100% to discredit my argument (which by the way is called moving the goal posts) then technically I had only disproved the breed of Christianity that allowed x% of allegory.

Yes, moving the goal posts is exactly what I am doing. And yes, it is ridiculous, and yes, you give convincing reasons for why the Bible is all nonsense. But I am simply moving the goal posts deliberately despite the fact that I know it's ridiculous in order to show that whether it's ridiculous or not you still can't disprove it.

Except you can only avoid the arguments via allegory-incrementation for so long before you yourself start producing impossible scenarios that show Christianity is not the truth:

Some interpretations of Christianity can be disproved IMO. Not all, that's what I am trying to demonstrate.

How can Jesus literally be God incarnate but allegorically hold this divinity?

Because if divinity is allegorical then God isn't necessarily "divine" in a sense that we use the word. He could be powerful enough to create the universe but not omniscient, omnipotent, omnipresent or divine. "Omniscience", "omnipotence", "omnipresence" and "divinity" could all be allegory. So Jesus being God incarnate could just mean that the God who created the universe embodied himself in the man called "Jesus Christ".