I'm atheist. I went through a period of saying I was spiritual rather than religious, then I said I was agnostic, then agnostic atheist before finally settling into atheism.
I can't say I'm an Agnostic atheist because although I don't know, my current belief is that there is no god. After all, I'm not an agnostic unicornist, I just don't believe in the existence of unicorns. Show me evidence for either and I'll change my beliefs.
Similarly I realised that what I was calling spirituality was actually entirely within the natural world. My reverence for nature or that feeling of awe looking up at the stars was a result of the amazing capacity of my human brain and not because of something "more" than reality.
I have to say though that if, incredibly, the god of the bible did suddenly manifest themselves unmistakably, I would become a theist through not having any other choice, but I would not become a worshipper. The horrific things that god has done, the malicious, cruel, but above all, stupid decision to hand out their instruction manual to a tiny group of people in the form of a book! And then leave it in the hands of countless scribes and translators so that almost any interpretation can be taken from it.
That alone would make me rather die than submit to being ruled by such an inept overlord. But when you take into account the cold cruelty of what would then be revealed as their creation: The orcas playing catch with a live baby seal, the Ichneumon wasps laying their eggs inside living caterpillars which are then eaten from the inside while still alive, the mallard ducks gang raping females to death and, of course, the worm that eats children's eyeballs. If a god manifested themselves and took credit for creating that deliberately then I say shame. shame on you, now kill me and be done.