My deduction is that a creator must exist and that He has communicated in some manner. Prophecy and miracles are the evidence of His existence outside of time and space.
I’m writing from the perspective and assumption that the Bible is divinely inspired; but that implies it must be internally logically consistent.
There is a lot of evidence that contradicts your claims. However, people believe what they want regardless of the evidence.
Having myself deduced as you have that a creator would communicate to honest seekers of fact, I have learned that humanity, and not just one tribe exclusive of others, has sought guidance. All creation has that same creator, after all. I have a container garden in my yard from which I draw sustenance. I water all the crops and they all bear fruit, not just one of them.
When I read your careful considerations that seemed to lead to another potential schism, that was the thought I had, to bring to your attention a question that can counter the forces seeking to divide us, in the hope your careful considerations might instead improve our understanding of how we are the same. Surely the creator created all of us, and the same consciousness informed our forebears tens of millennia ago, just as it does all humanity today.