First, one must define god to answer that question. As Isaac Asimov stated-"Any sufficiently advanced technology is inditinguisable from magic"- so if an advanced technology enabled an alien to appear from a cloud with a booming voice declaring itself god, would not millions consider it god?

I am "only" 99.99% certain based on preponderance of evidence. Absolute knowledge isn't necessary to draw useful conclusions. It's a false canard that 100% certainty is either needed or possible in any question, not just this one. There is no such thing as totally objectively proven facts. There's always wiggle room for uncertainty. I'm not 100% certain I couldn't survive driving 130 miles per hour through my neighborhood while drunk but that doesn't mean I'm going to try it.

The problem with theism isn't that we can't be sure there's no god. It's that there's zero valid evidence that there are any gods, and their fabulist claims set an even higher bar to being given credence than most garden-variety truth claims.

We know, beyond reasonable doubt, that there is no such thing as a soul and that the mind is an emergent property of brains.