It's not a matter of explaining it for me -- suffering is expected to exist if atheism is true since if atheism is true life adapts to the universe with limited resources; and imperfectly so -- therefore, suffering.
It's not so easy to explain if there is an omnipotent/omniscient God who is thought to be benevolent: there is a contradiction. An omnipotent/omniscient benevolent God existing at the same time as suffering existing is as absurd as a square-circle or a married bachelor.
Therefore either God is not omnipotent (can't prevent suffering), not omniscient (doesn't know how), not benevolent (allows or causes suffering), or doesn't exist.
Time frame. Adam and Eve were supposed to populate the earth.
Fill [not overpopulate] the earth with perfectly sound and healthy sinless people to live forever on earth.
Because A&E had no children while in human perfection then Adam, as our family head, could only pass down to us what he now possessed which was human imperfection of mind and body. Sin cause death. Adam sinned; Adam died. If we could stop sinning we would not die. We can not stop sinning so we also die.
More than Adam and Eve were involved in Satan calling God a liar.
Satan wants the worship from all humans.
So Satan set himself up as a rival ruler to God's Golden Rule.
To immediately destroy those three would have proven God's supreme power to angelic creation, but we would have never been born.
We would not know the truth about the penalty for disobedience being death.
At Job [2vs4,5] Satan believes if our 'flesh' is touched [loose health] we will curse God. Or in other words, apply enough pressure to us and sooner or later we will not serve God.
By Satan lying he calls into question God's right to require obedience from us.
By A&E disobeying that calls into question if all humans would disobey?
Satan claimed [Job 2vs1-5] that he could turn all of us away from God.
Time is allowing for us to be born and Satan to prove his claim, and like Job giving us the opportunity to demonstrate who we want to obey as sovereign over us, Satan or God?
We can all prove Satan to be the liar, and as a loving son or daughter would want to clear their father's name from all false accusations or charges,
so we can loyally do that for our Heavenly Father.
According to Revelation a happy outcome is certain.
Rev [22v2] says there will be healing or curing of the nations.
So this system we live under [2Cor 4v4] is temporary.
Temporary until we die, or if we are alive at the time of Jesus 'glory' [or involvement into mankind's affairs] then we can continue to live right into the start of Jesus 1000-year reign over earth with the happy climax of reaching human perfection of sound mind and body as Adam originally had, and welcome back most of the sleeping dead to also be part of the humble meek that will inherit the earth. Inherit a beautiful paradisaic earth when only righteousness will dwell.
And as Isaiah [33v24] foretold that: No resident will say, "I am sick."