I really love your approach on discussing "toxic people" and it's really nice that you described the narcissistic personality traits some of them possess. I have studied narcissism in non-clinical population recently and I really appreciate your content!
What I would like to add to your thoughts is just that sometimes these people are not so much narcissistic, rather they could be insecure and afraid of new relationships. Being toxic is their first "defensive mechanism" but once you get over this barrier you might discover a harmless and good person in general.
All the best to you, as always :)