If there's no god, why does guilt exist?

It's advantageous for humans to work together to survive, rather than try to go it alone. And it's difficult to work with someone you don't trust. So tribes of humans that evolved things like guilt and empathy fared better than those that didn't.

Guilt is a consequence of empathy, and empathy's purpose is building functional cooperative societies. I get that aspirational youngsters could look up to psychopath CEOs or rich weirdos in general, but what would happen to society if everyone was a psychopath? Murder and abuse left and right, with no one to trust, with everyone only looking out for themselves and using everyone to try to get a bit more money, it wouldn't take long for society to collapse.

Empathy is really the only thing holding us together, and the most functional societies with less poverty are the ones whose governments cover the costs for things like education and healthcare.

It beats me, I don't know who I am, maybe there's guilt thanks to morality and not because there's a false god, no recognisable deity exists in the cosmos, also we're all insignificant.

humans are social creatures and in society right and wrong are determined by how it benefits the group not the individual

but wile also knowing that the individual is what make up the group

its an evolved trait of most highly evolved creatures

What created God? Did God just appear out of nowhere, or did something else create him? If that's the case, what created the thing that created god? What created the thing that created the thing that created god? Why did God create an entire universe with hundreds of billions of galaxies, just to populate 1 single rock? Is your god even the correct one? I mean, there are literally thousands of religions across the world. Maybe it's actually Odin or Zeus who is the correct one, and you've been praying to a fake one all along?

Because there is a God.

I can think of dozens of reasons of how guilt is evolutionarily advantageous. Most of whichinvolve men "taking care" of their progeny

Guilt is a way for us as humans to recognize when we have done something bad so that we can correct our ways and improve as a person. It has nothing to do with religion.
Its true that people like psychopaths very often hold positions of power, that is why there is so much corruption caused by the people in power, but there are also lots of disadvantages to lacking empathy. For example those who lack empathy live miserable lives and they can actually suffer from depression, as they feel empty inside all the time. They also are more reckless than the average person which often puts them in danger. I dont see any positives in that in terms of survival, and as humans we are driven by survival mainly. I also believe we are on this earth to learn and evolve. Those whose lack empathy cannot do much evolving. They are broken people.

I think you're wrong on pretty much every single point you made here.

Guilt is a social response, not a religious one. People in positions of power don't feel less guilt, they are just perceived to because too many people are relying on them (so they don't quit or kill themselves early) and their sensitivity to it erodes over time (so they're colder later in life). Guilt doesn't prevent people from reaching their full potential, either, since guilt is a reaction. You don't feel it before doing something, only afterwards. If you were going to do something amazing, the only way guilt would stop you is if it involved stepping on someone's face very early in your career. Most careers don't require that. Objective good and evil don't have to exist for guilt, either, because guilt itself is subjective.

Guilt should be analyzed from the same standpoint as any other social interaction. Why do we feel guilty? It's because we did something that we feel was wrong. How does that help us? Because it reinforces right and wrong in our minds as a reaction to social stimuli. If your sister pinches you, she should feel guilty concerning the action so she doesn't keep doing it. That guilt could come as a reaction to you being in pain, or crying, or no longer playing with her. If she doesn't feel it, even if she's chastised she's probably going to do it again.

There is a God, and we know this because of guilt. Per "Mere Christianity" by C.S. Lewis