Hi Katy,
I am a non. But we are discussing this very topic in the SOFF forum. Enclosed is Riso and Hudson's belief about different PD and the 9 Enneagram personality styles.
Complete list ( Authors Riso-Hudson)
type 1: Obsessive-Compulsive
type 2: Histrionic/Dependent/Somatization
type 3: Narcissistic
type 4: Borderline/Avoidant/ Narcissistic
type 5: Schizotypal
type 6: Passive Aggressive/Paranoid/Dependent/Borderline
type 7: Histrionic/Manic/Bi-polar
type 8: Anti-social
type 9: Passive -Aggressive/Dependent/Schizoid
Link for your type 4:
https://www.enneagraminstitute.com/type-4/It is all theory and conjecture, and no definitive conclusions can be reached, but some of the information has been very valuable for me personally. I am a type 2.
Be well.