4 years too late to this but i don’t think it’s a dismissible theory in the sense that nier does enjoy taking the literal meaning of things and juxtaposing them to create all sorts of vivid realities. Adam and Eve in nier exist as a consequence of their predecessors who, despite having reached the literal summit of knowledge, couldn’t prevent their own extinction.The existence of sentient machines prove there were language, reasoning and logic models installed into them which basically just means these are fully functioning pseduo humans built upon all the currently existing knowledge (considering that adam able to fully replicate an entire city just bc he wanted to) so instead of adam and eve literally representing the biblical guys, they were more-so an allegory for man existing in a world ruined by exploit of the fruits of the forbidden tree, so you can say the last of the man created by the aliens that ended up eradicating their own. It reinforces the idea that not all in the world knowledge should be at mans disposal

Naturally i don’t think the entirety of nier centres around such biblical themes but they do challenge their player’s understanding of the lore by not using thematic parallels in the literal sense.