This is too big a problem for me to solve. I have tried. This might just be one of those things that drags on & on without really getting anywhere. Bit like religion for the last 2,000 years folk are just never going to agree because the evidence for either side is just too primitive to analyze with any degree of accuracy.
I think as a species we have delusions of grandeur about how advanced & civilized we are, I hope future generations will figure it out. We are achieving groundwork for them if nothing else, I'm not confident that our generation will ever get to the bottom of it.