Hi Olympia!
Welcome to our online family! First let me say it takes a while lot of courage to reach the place you have.

I have reached the point where I cannot continue the dynamic that's been there all my life.
I think this is one of the major first steps in this journey to healing ourselves. I came to that same place a few years ago where I couldn't keep going on as I was, but I didn't know how much it was related to having an uBPDm. There is a great list on the right side which is a good place to start. Any sentence you click on will open up with more explanation. Where do you feel you are on the list? It is not necessarily linear and everyone travels at their own speed.
I realised tonight that I have been trying to protect her from herself, as well as myself from her rage, and it's has a massively detrimental effect on my mental and emotional health.
As children of a pwBPD, sadly it is entirely too common for us kids to have stepped in to this place of protecting them. It was our means to survival. I am sorry that you have experienced the same thing that so many of us here have walked through. It is quite an astute observation.

There is a wonderful book that has been so helpful to me which discusses the topic of what types of things an adult child deals with as they begin to recover. I'll post the link for you below.
Surviving a Borderline ParentPlease keep posting and reading. We are an online family with members dealing with a lot of similar issues. You are not alone.
Wools