An afterlife would be terrifying for me

[Apollo]

so all your stories and ideas are going to reflect your present lifestyle and aspirations—unlimited supply of sex and food would do it without much worrying about predators.

The kind of afterlife described by Augustine, Aquinas, Dante, Boehme, and many others, doesn't resemble this at all. 

What argument can you present to show that their ideas originate in hunter-gatherer fantasies of comfort?

have started seeing the logical and scientifically clear flaws in the story.

I think you may have historical flaws in the just-so story you've told above. 

There may be logical or scientific flaws in the theological views of an afterlife, but you'd have to know what they say in order to address them.

Of course every culture and generation further adds to the idea in favor of (and not the contrary). If Mo told the exact same thing about god and afterlife as Jesus or jews then how he’s going to get his own cult going. But the point is that these are all offshoots of original ideas of a plentiful happy life without giving much thought to what is happiness to begin with and what are its various forms and sources (only speaking in terms of heaven and not hell).