Toxic friend gets all the attention

I won’t lie, it does make me jealous that she gets so much attention but t wouldn’t bother me if she was a genuinely good person. I’ve been friends with this girl for a year and she is generally a really sh**** person. She treats me like absolute trash, blanks me when she feels like it, purposely makes me look dumb in front of other people and third wheels me wherever possible. I’ve remained friends with her because we’re part of a rather tight-knit group and she can occasionally be pleasant.
Although it shouldn’t bother me, it is frustrating to see someone as horrible as her get so much attention. She’s very pretty and small, so guys are constantly throwing themselves at her. She purposely leads on these men, flirts with them etc with absolutely no intention of ever getting together with them. After a month or so, when she’s tired of talking to them she blocks them on social media. To me, it’s so horrible to play with somebody’s feeling like this. She never thinks about the consequences however, because there is just an endless supply of men lining up for her, so she thinks it’s alright to treat them as disposable.
During first year, she sort of “stole” my crush (yes, I realise that this isn’t actually possible and I should’ve made a move sooner but it still irked me to no end). She was aware that I had a crush on this dude, and purposely seemed to spend a lot of time with him, choosing to sit with him over me in lectures. He pretty much ceased all communication with me and she would randomly shove her WhatsApp conversations in my face to show me how much they had been talking.
Just the other night, she coincidentally met up with my other friend (who is also my flat mate) and the two exchanged numbers and got to know each other. This sounds way too deep but I honestly feel like this is such a huge intrusion on my personal life. I had incredibly bad luck with friends during first year and I genuinely get along with my flat mates, my flatmates and my uni friends are like two separate spheres. I’ve been avoiding this girl in lectures because she just gives me too much negative energy, so the fact that she’s now in frequent contact with one of my flatmates is just... unsettling to me.
To everyone, she seems really nice. On a surface level she maintains this really pleasant persona, but she’s actually a complete narcissist. The kind of person who if I tried to talk things out with her, would get defensive, tell me to F off and then sh**-talk me behind my back.
As I said, this shouldn’t bother me but witnessing someone so undeserving of attention getting it in such large quantities is really annoying.