You should check out Carl Jung's Answer to Job, he held an opinion like this about the devil as a divine aspect, as God's shadow-self maybe, and how that encounter with the infernal self eventually led to his incarnation as Christ. Carl Jung is a genius, I can't recommend his work enough, I love where you're going with this and I think you'd find something to like in his work. Man and his Symbols is a good book and easy to read.

Just my thoughts on it, and I say this as someone who has next to no formal religious education so I apologize if I say something wildly stupid:

'The devil' is a tricky being, because at least in modern Christian theology he's really two beings: on one hand he's the Shaitan, who deceives and misleads, the goat, the lecher and the apostate, the master of illusion. Shaitan is the crawling snake, who was cursed to go on his belly, he's a cthonic underworld figure.

But on the other hand he's also associated with the Lucifer, the angel who fell: the morning star, the illuminator, the bringer of light. He's the snake on the cross, the caduceus, the raised snake of Kundalini.

Sometimes I wonder if it was that light-bringing aspect that led the allegorical snake in the garden to tempt Eve to eat of the 'fruit of the tree of knowledge', the forbidden fruit, the fruit of sentience, of identity and ego. When Adam and Eve had eaten of it, they 'saw their own nakedness': they realized they were naked: they had self-awareness, ego.

And once they had ego, could they have possibly stayed in Eden? Once they had ego, they had fear. Anger, greed, desire, ambition, will. Infants don't have selves other than their mothers, but when the ego develops, that's when that tension sets in, and one can't stay in the womb forever.

I'm not sure, I've been thinking on this a lot too.