"I am an atheist, out and out. It took me a long time to say it. I've been an atheist for years and years, but somehow I felt it was intellectually unrespectable to say one was an atheist, because it assumed knowledge that one didn't have. Somehow it was better to say one was a humanist or an agnostic. I finally decided that I'm a creature of emotion as well as of reason. Emotionally I am an atheist. I don't have the evidence to prove that God doesn't exist, but I so strongly suspect he doesn't that I don't want to waste my time." -- Isaac Asimov, "Free Inquiry", Spring 1982, vol.2 no.2, p.9
i will add what asimov either has said elsewhere or assumes we already understand: that it is not the atheist's job to disprove any god's existence, not least because you cannot disprove someone's existence but also not least (maybe even more importantly) because there are so many gods whose existence cries out for disproving that it would take a lifetime to get through half of them even if you found a way to do it, and since there are no gods, this is the only lifetime each of us has got. what a stupid way to spend it!
I to faced the same dilemma of not having proof God doesn't exist. And like you discovered, you cannot prove the non-existence of a thing. You can only rationally assume it's non-existence by the lack of evidence.
At some point you have to stop looking.
There was a funny cartoon one time that started out with what appeared to be a man flapping his arms flying along several feet above the ground at high speed. When suddenly he crashes into a a wall with bodies piled up on it. The camera rotates and you realize the ground was a cliff side and the wall the ground. You travel up the cliff side and there's a line of men with a king like overseer at the cliff edge who commands the next person in line FLY and kicks him off the edge.
At some point you have to assume your search is futile. Looking for a god that has no evidence of its existence is a waste of time.
There can only be two conclusions;
1 God exist but but he has completely and perfectly covered up its existence creating fake evidence to hide the true nature of the universe. Like fossils of animals that never existed and starlight coming from galaxies billions of light-years away. ( it is created in flight with a false history attached to it)
This is all done so seamlessly that we cannot tell the difference between a natural universe and one that was created and is controlled by a supreme deity able to commit miracles and cover it up with omnipotent complete forgeries.
2 God or gods do not exist.
Feel free to apply Occam's razor.