When I say that suffering entered into the world when Adam and Eve acted the like atheists, I'm saying that they acted in a manner that is independent of God, not that they denied God's existence. Atheists, of course, operate in their world without considering God as either existing or as an explanation for knowledge, rationality, morality, or existence, etc. They act in a manner that is self-determining of truth and morality.

Following are some of the ways in which the actions of Adam and Eve were atheistic which then brought sin into the world and with it suffering. Adam and Eve acted like atheists when they behaved independently from God in the following ways.

They abandoned God's revealed word about not eating the forbidden fruit (Gen. 3:1-6)
They decided for themselves what was to be believed or not regarding truth about what God had said.
They decided for themselves what was morally right and wrong.
Eve (and Adam by following) used her own experiences and preferences to judge moral truth (Gen. 3:6)
Atheists regularly complain about how God allows varying degrees of suffering in the world. I often respond by saying, "Don't blame God. Blame Adam and Eve when they acted like atheists. That's when things went bad." Atheists, of course, don't like my response because it puts them on the hook. But it is true nonetheless. Furthermore, most often they miss my point, and I have to explain it to them by listing out the things I provided above.

God let us have our independence and its consequences
Generically speaking, God gave us, Christians and non-Christians alike, what we want: freedom to act independently from Him. Adam and Eve behaved in a manner that was independent of God's revealed truth and righteousness. First, God allowed them to rebel. Second, God allowed them to suffer the consequences of their rebellion: separation from him and sin in the world. These consequences include hard labor, birth pains, plagues, famine, sicknesses, suffering, etc.

Are we children or grown ups?
Furthermore, if God is obligated to stop suffering, according to the atheists' rationality, then I ask them at what point, or what level of suffering ought God to intervene? Do the atheists think that God must stop all physical suffering or all unnecessary physical suffering? If the latter, then who decides what unnecessary suffering is? What about emotional suffering? Should God stop that as well? But why stop there? What about the suffering that people bring upon themselves because of their free will choices and actions? Should God intervene and prevent them from making those free will choices as well? Or, should God let them experience the consequences of their rebellion against him?

From what I've seen Scripture because we are made in the image of God (Genesis 1:26), we have responsibilities consistent with that image. We have obligations given to us by God such as taking care of the earth (Genesis 1:28). In this, God treats us like "grown-ups" in that he lets us be responsible for our own actions. He doesn't treat us like children and stop us from doing every bad thing. So I can't help but wonder if the atheists want God to treat us like children and intervene at every, or almost every instance that might bring suffering.

Conclusion
I think is clear that atheists decide for themselves what is true, false, right, and wrong. They do not humble themselves before God or consider his self-revelation in Scripture and the person of Jesus when they make their decisions. Adam and Eve behaved similarly when they decided for themselves what was true, false, right, and wrong. The effect of their independent rebellion is suffering in the world. So, when atheists complain that the Christian God ought to stop "unnecessary" suffering they have failed to consider that biblically speaking, it was behaving like atheists that caused the suffering in the first place. And, how does an atheist determine what is unnecessary suffering and at what point ought the Christian God intervene and stop it? Should He intervene and stop the free will choices of those who bring suffering upon themselves? I'd like to see atheists try and answer these questions before they complain about the Christian God.

https://carm.org/suffering-entered-the-world-when-adam-and-eve-acted-like-atheists?fbclid=IwAR143tFLab2dlVVahA4ZiojwtwdEzFu8t_f5wt7BmF5vkd0W98JnpgRpkic

The devil at a point also acted in a manner independent of God.

And he remained perfect in his ways until iniquity was found in him (verse 15b). What was this iniquity? We read in verse 17, “Your heart became proud on account of your beauty, and you corrupted your wisdom because of your splendor.” Ezekiel 28:15-17

Adam.and Eve is not a real story. Even the Jews that wrote that story believe that it was metaphorical

I agree with you for most so-called atheists are "Adams and Eves" using atheism as an excuse for their rebellion against God.

For the difference between then and now is that Adam and Eve had the proof of God's existence, so they couldn't use it as an excuse for their rebellion against God.

For it was any excuse they could find then, such as "it was the woman..." by Adam, "it was the serpent..." by Eve. So if they were here today it would likely be "it is the lack of proof of God's existence"!

For it's has always been in man to make flimsy excuses to justify his rebellious tendencies, so even if the proof of God existence was provided, most atheists as Adam and Eve would yet be rebellious against God.

Thanks.