Yes, I guess the issue is if everyone is a complex individual with diverse presentation if it makes sense to have a binary “you have it” / “you don't have it” diagnosis.
Here's one article on anxiety vs adhd: https://childpsy.org/anxiety-or-adhd-the-diagnostic-confusion-that-derails-childrens-mental-health/
It's pretty obvious that psychiatric diagnoses follow trends, going from underdiagnosed to overdiagnosed; with the possible exception of the rise in bipolar disorder, which is probably due to a boom in anti-depressant medications “revealing” mania, which at least some doctors are beginning to acknowledge.