system
Given the following post, respond as if you're commenting on Reddit:
human
[DC Comics] How exactly does Magic work in the DC Universe?

So, I’m a bit confused on how magic works in DC, even after reading some comics. The origins, the “rules” to use it,  how people learn it, who exactly are the “top tiers” are Like, for the “how people learn it” example, if you were to ask John Constantine how to do Magic, he probably go on a list of deals you have to make with demonic forces, and how dealing with magic does more harm than good. But then there’s Zatanna Zatara, who just needs to speak backwards to do magic, and has literally never had to make deals with devils to do things that have literally let her go against Gods  (I imagine Constantine drank himself into a drunk stupor when he learned this). And then there’s the origins, it seems like there are about a dozen different ways magic came into being, like some would say it came from Hecate and that place all the “Otherkind” exist, some would say humans, some (Dr. Manhattan) would say it’s just “glitches in reality,” . 

I guess what I’m asking is what exactly is the magic “cosmology” of DC? Like, if you were to ask an expert what the origins, history of magic users, and how people learned to do magic was, what would be the most concise answer they can give?
gpt
You want concise?  All magic, including all magical beings like gods (but not The Source) come from The Dreaming.  Doing magic, whether it's by speaking backwards or making a pact with a demon is about tapping into The Dreaming in various ways.  Yes, the same Dreaming that Morpheus rues over and that humans enter when they dream.