Monk does a decent job of showing some OCD. Realize that some of it is what’s easier to show on a TV program.
As Good As It Gets is older than Monk. Jack Nicholson portrays someone with Hollywood OCD, so cleanliness, certain “rules”, etc., but it does show how difficult relationships can be because of OCD.
Monk illustrates more than just the classic Hollywood idea of OCD, but it’s also a comedic mystery/crime show. My therapist who diagnosed my OCD actually suggested Monk to me. I’d have a lot of fun catching the one or two times it seemed the writers slipped up, but also, sometimes our OCD “forgets” to torment us so badly.
I really recommend that show, not just for OCD portrayal.