I don’t know if this helps and probably wouldn’t help convert anyone, especially Atheists, but I had a Jewish person email me an interesting perspective. I have since deleted the email and lost the link to the website he directed me to, so below is my best attempt at paraphrasing what he said.
For there to be LOVE, there must be a need or something missing. IF we are completely satisfied, happy, content and have everything we need, then there is no need for love and no reason to look for it or accept it from others. - In other words… a separation of some kind.
Therefore, the fall of man, had the side benefit of creating a need for which God’s love can be the answer. A separation which has the chance to lead to love.
One could argue with this that God is perfect, has no defect and yet he Loves - But he is not human. This applies to human philosophy and nature, not God.
One could argue that Adam and Eve loved God BEFORE the fall. However the bible doesn’t spend a whole lot of time on this and we could argue that their love was immature, untested, and obviously not complete enough to keep them from sinning.
But regardless, we should be able to both agree that after the fall, there existed a greater opportunity for the choice to love God more freely due to our separation then if it had never happened and our soul did not have that void or longing.
I would add to this idea, a very common idea - that we often do not appreciate or recognize how much we love something until we lose it. I think our separation from The Father is the source of this universal truth. That we know NOW that sometimes we don’t know WHAT we have, until we have lost it.
I don’t intend this to entirely explain the fall, but I think it is an interesting idea related to it and perhaps says more about the human condition then WHY the fall was necessary. But I still think it needs to be brought up.
Love often times requires a need or a longing - a separation.