As that Wikipedia link points out, the version of the word based primarily on the Greek child who didn't want sex is "Narcismus". The -ist suffix is distinctly un-Greek, and comes much later than Lord Byron.
It's interesting that you point out the word "ps*chopath", which is Greek for "suffering soul" and is often used to attack people with ASPD. I can understand why people in the 1800s would hate those whose souls suffer, and those who are like Narcissus. But surely in 2026, you've grown out of such queerphobia and ableism?