How do I confront an emotionally unavailable (avoidant) friend? I'm sick and tired of panicking whenever I reach out to her.

Hey Redditors, I know the right thing for me to do is to find the courage to meet new people (and try to heal my mental health), but this is dilemma is eating me up on the inside. Here's a bit of context:

Me and Jenny (said "friend") were friends in undergrad. We both bonded over feeling lonely, having dysfunctional families, and being stressed out over schoolwork. In spite of our similarities, I always admired her for being blunt and assertive; she probably admired me for being a "genuine" and understanding person. Even though we saw each other a few times a semester, I didn’t mind. Every once in a while she didn't respond to a text, but that was fine with me. However, over the years - especially after graduating, it feels harder to keep in touch. For instance, if she initiates a text conversation once or twice a year she will keep it going for 2-3 days before "shutting down" - but if I start one, it's all up in the air. Who knows if she was more reliable in college since she was away from her issues going on at home?

How should I reach out to her - to let her know how I feel i.e., call her, text her, or leave a voicemail? What if she doesn't respond to any of those? Should I give examples of when I felt bothered by her inconsistencies - or would that sound too harsh? Should I tell it to her in a softer manner - about how my anxiety makes me triggered when she doesn't respond and acts flakey - and this doesn't going to work with me? Should I tell her I want to cut her off as a friend, or give her another chance? I feel so confused and unsure ;(