Not exactly. Actually I'm wondering what's the difference. As far as I know, God ceased to mess with our world a long, long time ago. And if God created the universe, what created God?
So we're left with either the universe that explain itself (it just is), or a God that explain itself, and created the universe (and then left it alone). God is a bit like the Dragon in my Garage: everything happens as if it wasn't there.
So, my preference simply goes to the simplest explanation: that there is no God. I don't expect you to have the same preference. But I do expect you to either acknowledge that there is no difference, or to eventually identify those differences.
So, do you think there is a difference between "God exists" and "God does not exist"? Do you think his (non) existence would change your life? Do you think you would observe different things in either case? This is the question I think everyone on this planet should think about for 5 minutes. Once you answered it, you basically have defined your God, whose existence is now either refutable or unimportant. In one case, science will likely find out (eventually), and on the other, well, I don't care what one believes.
Pythagoras (570-495BC) had a belief in a spherical earth along with a number of other Greeks in the same era.
The book of Isaiah was written no earlier than the 8th century BC.
These two date ranges and regions are quite close to one another. Your claim seems a bit off the mark.