If Good and Evil truly exists, then does that not confirm the existence of God?

One could argue Christianity, and all theological structures, were built by societies as a way ascribing greater significance to what good and bad really are and what they entail. As a stronger motivator for the people to follow these rules and (thus) the rulers who established them. You may notice that throughout history governments incorporated religion as the foundational basis for following laws. Whether God was real or not, this served to give the laws of government a deeper and more powerfully rooted relevance. It helped sustain societies. Because the fact is religion promotes structure. It is thus in government's best interest to use (ie make up) religious guidelines and premises (as government is of course a system that can only exist by structure/order). One could consider this concept in relation to systems of order such as the Mandate of Heaven, a historical term you could find details on-online.

You speak of good and evil as if its some immutable fact. But truth is, it isn't. Humans may generally agree on good and bad behavior but there is no existential objective standard for it

Allow me to try to attempt

We, as humans, are either born evil or born good. And that doesn't mean we are following the ideas of God. Take the study of Adrian Raine for example. His study finds that people can be born evil through psychological terms because their brains had abnormalities which leads them to do evil acts. to use the argument that God made those abnormalities starts another debate like why does he allow such abnormalities to pass? Abnormalities that could lead one to rape, abuse, or murder.

Besides, your argument could also be argued as false because the Bible has two testaments, both of which share two different versions of God and the idea of good and evil and how God views acts of sin. In the Old Testament, God is more punishing, in the New Testament, he is more forgiving. The idea of sin also changes. Anything can be considered a sin in the Old Testament because, again, God is less forgiving. But the New Testament argues that the idea of sin is more relaxed and therefore, the punishment is too. So which testament are we are we talking about here?

The idea of good and evil dates back to the beginning of time. The Bible in which the first idea of sin was written in was written in 20th century BC. Sure, the idea of a God dates back even further. But that is if we are talking about Buddhism. Buddhism is the first recorded religion. The God me and you know didn't exist until the Bible was written in 20th century BC. Meaning the people in the caves would have no idea about the idea of sin because there was no scripture to tell them sin is real and if you commit sin, you will go to hell. After the Bible was written, only then did the idea of sin and heaven and hell was made. But you can't say we have always thought that way when the cavemen weren't living like that. Because if they had the idea of sin in their mind, they would not have been raping women or murdering people for their flesh to eat, because they never knew. If we knew since the beginning of time, we would be living morally because we would have grown up more morally. Following that same logic, we wouldn't have crime anymore because we have always grown up in morality and we would have been raised in morality.

Don't get me started on all the different types of Christianity with their many rules behind sin and good and evil. Your rules may be different to those rules of the Amish or the Catholics.

Granted, I am not a Christian, so I apologize if my facts of Christianity are incorrect and do feel free to correct me because I love to learn. But I am a history student with many years in by belt so I'm pretty sure I got those things right. That's my argument, thanks for reading.