Several people have latched onto the idea that "in fact, harry is in a simulation [because it's fiction]". This is a deeply confused statement. [edit: I misread Argency; he's just speculating - no [because it's fiction] implied - I replied to the wrong comment]

A story can be about anything, and is exactly as meta as its author wants it to be. We've seen Harry use the idea that he's like a hero in a story as an intuition pump, but that's part of the very non-simulated [fictional] world he inhabits :)

I mean, the story events so far could turn out to have been simulated, or we could end up with a story where self-aware fictional characters negotiating with their creator, but I've seen no indication of that so far.