ultimately I'm giving her what she wants a sidelined family
I disagree. That's all your internal stuff being projected onto her. It is completely coming from you.
I've finally realised she thinks more of her friends than she does of her family
Complete projection based on how you feel inside and your trauma. You don't know what anybody thinks other than yourself.
She's not once thought about me being alone since the passing of our grandmother
Again, projection based on your own pain. You cannot possibly know what thoughts she has had. Don't punish her because she wasn't equipped to be the support you needed in this loss. Your aloneness is not her fault. How much pain it causes you is not her fault.
You both had severely traumatic childhoods and adult lives. You've both had a really shit time of it.
You're attaching huge amounts of symbolism and meaning based on how that trauma has affected you, and punishing her for thoughts you've decided she has because she doesn't behave how you want and need. Your internal, pre-existing pain is adding punches to things that wouldn't exist otherwise.
Your experience of trauma means you want her close and interpret behaviour in certain ways. Have you considered that her experience of trauma - given she is a different person and was a different age to you when your Nan took you in - means she sees things differently? Feels things differently? Interprets things differently?
Maybe finds it painful to do the things you want from her? Finds closeness painful? Can't cope with your grief alongside her own?
Just because she can't meet your needs in the way you want doesn't mean she doesn't care about you.
She kicks off at you because you can't meet her needs (and you get indignant about that because you don't recognise her needs), you kick off at her because she can't meet yours (and she gets indignant because she doesn't recognise yours). Where does that get you?
You feel how you feel and that is your right. She feels differently. But acting on those intense emotions in the way you intend is going to bring unnecessary extra pain into your life. Please don't do that to yourself, you've hurt enough.