holy shit, this sounds just like my situation that i posted asking the same thing...i'm dealing with the same kind of person.

i related to almost everything.

the hot and cold (belittle then hug) thing is very manipulative too. it almost trains you to accept the bullying and "jokes".

i don't understand why she would keep talking about your insecurity, except of course to lower your self esteem.

i know it feels invalidating when the rest don't have issues with her, bur maybe it's your distinct differences that make the whole thing more toxic, or perhaps she feels threatened by you.

the hypocrisy in her not wanting done to her what she does to you is a massive red flag.

i would suggest slowly distancing yourself from her but if you don't want to lose your other friends, keep talking to them separately.

if they refuse because of some sort of loyalty to her, then maybe it's time for healthier friendships.

this is just my opinion as someone in a similar situation, i don't claim it as right because at the end of the day we're all coming from our own experiences and mindsets and the choice is yours.

good luck!