If you enjoy the realism/grounded nature of the movie, it’s gonna be hard to find similar shows in anime, especially nowadays as everything is just romcoms or fantasy. Movies tend to be have more options in that category (check out the director’s other works).

In addition to Paranoia Agent, I would say maybe check out Monster? It’s a 60 something episode show about a doctor who saves a child’s life who turns out to be a serial killer, and now the doctor has to come to terms with killing him ‘for the greater good’ as someone who’s supposed to save lives. I haven’t finished it, but it also deals with nature vs nurture and some other stuff.

There are some genuinely creepy stuff in my opinion. I never liked the outro as a kid because I would be too scared to sleep lol.