Read the spoiler, thanks to everyone that reacted to the spoiler so that I could read it, and came to this conclusion.
Book isekai: When the author wants to write a parody of a terrible book that doesn't exist, so that he can write the terrible book and blame the memes.
It's especially odd when the MC says the book was "popular" but then proceeds to explain how terrible things are after poofing into the second world.