Hello and welcome!
Congrats on your success as a songwriter!
I am glad you are reaching out for support. It is so important to talk with others who get it. while some of the details of your story are different, overall the theme is one I have read here before several times so please know you are not alone. I am so sorry you have had to grow up with this sort of conflict and abuse but glad you are trying to change things now.
Her texts are all over the place emotionally; telling me she loves me one sentence and then angry and accusatory in the rest. She thinks me standing up for myself and setting a boundaries means I hate her and I wish she was dead instead of my father. (Things I would NEVER say and have NEVER said to her)
Give her time to settle with the new parameters of your relationship. It is a big change for you but for her as well and given that BPD is a disorder of emotional regulation, she will go through these time periodically and especially after you start changing the way you typically react and respond to her. Give her time to return to baseline.
I struggle with the guilt of feeling like a bad daughter for not speaking to her, but at the same time I know in my heart that being in contact with her isn't healthy for me emotionally.
Allowing yourself to recognize and take care of your own needs is excellent, but like I said above, it is a big change for you. You will struggle with your feelings as things might feel wrong or man or uncaring as you change the way you interact with her.
I'm trying to figure out how to do what's best for me without feeling guilty about it. Any advice from anyone who has cut their BPD mom out of their life?
I think it will take some time and practice before you can get to the point of not feeling so guilty. As you learn more about the behaviors associated with the disorder and how they influenced the way you relate to your mother, I think the guilt will change. Learning about the behaviors will also help with self-differentiation which will help you be able to consider your needs and those of others without ignoring you or defining you based on their view and opinion.
Have you had a chance to read other posts and look at some of the articles we have listed above?