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.
OR
2 God or gods do not exist.

Feel free to apply Occam's razor.