She is not capable of living alone. I'm her only child so this is all on me.
Right here. This is the issue.
I'm going to challenge you a little bit, and suggest that without you being aware, you may have been brainwashed to believe and feel this, and be her "caretaker".
She is an adult who has capacity to make her own decisions, including bad ones.
You are an adult who is entitled to live your own life without being held hostage to her bad decisions and bad treatment. Ask yourself, why is this "on you?"
What makes you say she is not capable of living alone? Can you tell us more about this situation?