This is like water on a stone. Over time, it can wear a person down. I’m so sorry you find yourself trapped in this situation. If the behavior is only directed at you, you may be a “lightening rod” for all of her unhappiness. If she behaves this way toward everyone, you are probably dealing with a mental illness. In either case, the person needs help that you and the family can’t give her. I hope you will work together to get her to a mental health counselor for an evaluation. With treatment, she may indeed make changes that will make life easier for her and for everyone around her.
In the meantime: Have you talked with other family members about how you might redistribute those responsibilities so you are not subjected to this every day? I just wonder if there is a way that others can give you some relief.
If you are really stuck there, yes, there are ways to distance yourself from the toxicity. Therapy is not only for managing mental illness. It can also be used to learn some new skills to manage a toxic situation. Give yourself the gift of a weekly support session. Your therapist will help you learn some new strategies for handling your family member and for mentally distancing yourself from her tantrums.
I wish you well.