The problem with framing Genesis 3 primarily as the introduction of humanity’s moral failing (“original sin”) is that it positions the human sexuality and child-rearing of Genesis 4 as part of that post-fall world.
But if the knowledge of “good and evil” is rightly understood as the experience of “joy/thriving and misery/suffering,” Genesis 4 accurately describes the human experience of such relationships. It is joy and thriving. It is misery and suffering. It is what it means to be human.