Genesis 3:12-13
It was Eve's 'sin'. Adam was there, yet the context informs, it was Eve who sinned. Otherwise, why is Eve questioned about it specifically.
So, you interpretation concerning redemption, is already a problem, aside from other things.
Actually, it was both. It was said Eve was deceived, but Adam sinned willfully when he followed suit. IMV, Adam carries the more weight because he knew better, didn't stop his wife or the serpent, and followed suit. Eve was deceived because she added to the words of God.
In Genesis 3:12-13 Adam went a step further... blamed his wife AND God when he should have owned up to his fault.
How is redemption a problem?