My sister is a work bully. She boasts to me about the things she has done or said to her coworkers. I feel sorry for everybody who has to work with her. She bullied me too. If you really knew her, you'd know at her core she is filled with zero self-esteem. Her extreme and jaw-dropping arrogance is a front. All bullies are like the wizard from the Wizard of Oz.
"Hurt people hurt". Someone once told me that. Not that it's an excuse or justification to accept her behavior. No. It is just to put things in perspective.
What I try to do when dealing with a bully, is say the third step prayer and fear affirmations in my head. I try hard to put up that "God shield", so as not to let the bully's spiritual sickness seep into my soul. I try to remind myself "This is a sick person. It is not personal."
Trust me I know where you are coming from. I spent decades in anxiety, depression, fear, major IBS, panic attacks, etc., because of dealing with abusive bullies. They are actually weak, sick people who need to bully to feel better about themselves. It does help me to see them for who they are.
Don't let her self-hatred seep into your soul and poison it. Give it to God and let it go. Ask God to help you. The prayer could be as simple as, "Please God, help me not let this sick person's behavior affect me."
Remember the Serenity Prayer. We can't change other people. We can only change how we let other people effect us or cause us to respond/react. She will never change. We have to change. I hope that makes sense. I'm not asking you to treat her different. I'm asking you to think about how you respond to her bullying.
It also might help if you pray for her. I know, you can get mad at me for saying that. Trust me, I know exactly how you feel. I almost didn't write it. But it works. I can't explain it. Say the resentment prayer for her every day for about 2 weeks. It will bring you peace and comfort.
I wish you serenity and peace.