I'm sure it's less accurate. Look how many people say they "have OCD" when they like a clean room. How many of those people understand that they don't actually have OCD?

However, current psychology is realizing the previous ways of lumping people with vastly disparate needs into finite categories is bad and dumb and doesn't really help anyone. Turns out, making someone's mental illness easy for nobodies to talk about isn't that useful for treatment, while extreme nuance and personalization IS really good for treatment.

You criticize self diagnosis but your criticism falls short because fail to actually look into how reliable professional diagnosis is.

It ain’t great!

I wouldn’t use the word “accurate” but professional diagnosis is so wildly unreliable that it’s hard for self-diagnosis to do worse. People give a lot of unwarranted credibility to professional autism diagnosis.