So I read a tok of comics, especially dematties stuffs as he is writer that references the Presence and have to say my theory was correct about the Presence.
Firstly I want to explain how the Presence is neither the light shown in the swampthing, or that is bound by Duality at all. In DR fate #6, It's shown that the Presence is the one who created creation, he is the smile behind the Universe and the one beyond mahapralaya. And that from his oneess duality came into being, good and evil, light and darkness, order and chaos, these are all duality. So the Presence is basically non dual, he is beyond any duality so he's not the light. In the same comic it's stated that the Presence is not someone with opposites but that he trancends it. He is beyond the notion of god and devil, mother and father, order and chaos, he is a god without opposites. So it's pretty concrete that the presence is not the light as he is someone who trancends the justification of light and darkness. He is simply without opposites, he is not the light for the darkness.
All of these are you know fine and all, but even in swampthing it's shown that the Presence is not the light.In Swamp Thing #75, it is stated that beyond mortal, demigods, gods, the war between light and darkness (referring to Swamp Thing #50), matter, all obstacles, there is God, one with the Void.
So this should prove that light ≠ the Presence. But I'll definitely argue it's one of his lesser aspects