You need to stop needing to get validation in life from her. She was a friend, but that ended. Now you arn’t friends. Maybe someday that will change. She proved to you that she was not and is not a dependable friend. If you were to get approval from her - what kind of sacrifices would you have to make? I don’t think it’s worth it. Maybe she is not mentally well. Maybe she is just disagreeable. But I say steer clear.
Get your validation in life from people you love and look up to. IE: your family, good friends, your church, volunteer work at a charity, from school if you go to school. If you don’t do things like volunteer or be part of some faith community - maybe it’s time to start. Look for real friends.
Your job is where you make money. You don’t have to like everyone, just respect them. If she starts disrespecting you badly again - just go back to the supervisor.
Going forward - just be civil to her and nothing more.