American Psycho (2000): Was it all in his head?

Okay, so I just rewatched American Psycho again and I'm even more convinced of my pet theory. The movie leaves it deliberately ambiguous, but I think a HUGE chunk of it – maybe even everything after he tries to kill Paul Allen – is just Patrick Bateman's fantasy. Hear me out. Think about it: the ATM that says 'feed me a stray cat', the cops not believing him when he confesses, the apartment completely cleaned up after all the... stuff that happened? It's all so over-the-top. And the ending, when he finds Allen's apartment is being prepped for sale and Allen called his office from London... it almost feels like a reset button. Like, imagine Bateman snapping back to reality, only remembering the murders he wanted to commit. He is a unreliable narrator after all. It is all in his head! I know some people argue that the ambiguity is the point, and I get that. But the escalating absurdity just feels too intentional to me. Plus, Mary Harron (the director, BTW, so I don't have "unknown" up there haha) has said she wanted to leave it open to interpretation, but that she personally believes some of it is likely imagined. That's good enough for me! Honestly, the thought that he might just be a deeply repressed, status-obsessed creep with violent fantasies is way more terrifying than him actually being a prolific serial killer. What do you guys think? Am I reaching, or is there something to this interpretation?