I think that our impasse is that we are talking about different things. You appear to be (correct me if I’m wrong) thinking of a god that is the creation of man’s mind. Probably the closest thing to what I’m thinking of if we wish to use what man has thought of would be the “Creator” “Nature’s God” mentioned in the US Constitution by the Deists who opined that there must be a creator (the watch maker) who could only be understood by observing the creation. But that’s not even what I think of when I think of the concept of a god because I can’t logically lay claim to the idea that there is a creator. The universe and all that’s in it could just be what is or there would be nothing. Another thing that will never be known, at least in my lifetime.
So I’m thinking of a possibility of a god that we cannot define where you seem to see the god that atheists deny as the ones defined by theists. There’s nothing middle of the road or wishy washy about the agnosticism of choosing to not make a claim about the unknowable. Can I be agnostic about the incomprehensable god and not believe in the god dreamed up by man? I think so since that describes my view. I’m sure you know the saying that an atheist just believes in one less god than a believer.