Narcissistic Personality Disorder is a real and documented mental health affliction. This is important to emphasize because there are individuals out there who can greatly benefit from using educational sources about it.
This also comes with the caveat of understanding that NPD is rare and can sometimes resemble other disorders—or simply put, many typical bad habits exhibited by most of us can be mistaken for it. I like to make the distinction between someone just being a pretty selfish person or acting in a way that comes off as narcissistic in the non-clinical sense, and someone who has a history of continuously behaving in a way that causes unrest and distress to those around them and possibly even themselves.
About your thoughts on a real, pathological narcissist being aware of having the disorder: there is documentation on this, though it's proven to be pretty abstract. There is a psychological term called insight, referring to an individual's ability to recognize and address their own symptoms or behaviors in general. People with NPD typically have very low insight—the disorder is considered ego-syntonic, meaning the individual tends to view their behaviors as normal or acceptable. This ego-syntonic nature is a hallmark of the disorder.
However, there is hope, because with time and patience, individuals with narcissistic traits can gradually develop a sense of insight. This would move them closer to the ego-dystonic category, where they are more likely to recognize problems within themselves and thus have more potential for effective treatment.
