Personally, I would try talking to her first. It sounds like this is a lifelong friend of yours, so you’re hopefully able to talk openly about how you feel with her. I understand sometimes people grow apart, but I wouldn’t want to lose a close friend without at least trying to tell her how I felt. Maybe she will change the behavior that makes you feel used and show up for you more? Maybe she’s going through something too and is just really busy? who knows. I hope you guys can work it out though!
I don’t let go of my long term friendships it goes through phases which is fine with me I just let them do what they do naturally no pressure as I don’t personally find it necessary to do so. Distance is fine for me if they fall back i do also if they lean in I do as well
This happened with me and a girl I knew from 5 years old she just stopped trying, it was always me asking her to meet up and I got sick of it. Since I stopped trying I’ve never heard from her again and we were friends for 25 years. it’s sad but if she cared she’d be there.