God, or any deity or hosts of deities, are completely supernatural.
Are they? That's hardly undisputed. In fact it's fairly tenuous for you to make any assertions about qualities that God has when we haven't yet definied what God is.
And moreover, if the natural world encompasses everything that can interact with physical objects, then how can anything be "super-natural"? At the very least, how can anything be "supernatural" and still be expected to have some kind of effect on the natural world? And if God or gods can't affect the natural world, in what way can they be said to exist?
They act on the physical world through supernatural mechanisms (I know, I know, if it affects the physical it is a physical mechanism, but just humor me for the moment).
This sort of acts as a proof by contradiction - since the existence of God in the universe leads to an outcome that is incoherent (physical mechanisms that are not physical), God must not exist.
Or maybe not. I'm not very good at proofs.
Atheists take this lack of knowledge and transfer it to a lack of a deity/deities. I, as an agnostic, prefer to leave it at "I don't know".
But some Gods you can know. For instance, if we propose a God that is omniescent, omnipotent, and maximally benevolent, we know that God does not exist.
I'm atheist about all gods except the minimally detectable ones; like you I must be agnostic about those. But who gives a damn about a god that can't do anything?