None of us can diagnose her here. We are just peers. Your mother has done some seriously abusive behavior. Some of it, my mother did, too. Though, my mother was not too extreme and has also been mostly good (thankfully for me). The story about the knife and ‘should she kill herself?’ Was way over the top abusive. I’m sorry you experience this.
Read articles on PC about all the toxic behaviors and personality disorders, also what healthy relationships should be. You sound like in spite of it all, you have it together.