From what you have shared of your mother, she convinced you to give in to her need to create drama to secure her need to experience a sense of relevance. Unfortunately she likes to create drama to feel alive. Yet, it’s become part of her character to the point that she fails to see how toxic her drama hobby really is. Plus, given the age difference between you and your sisters, yes you were alone with her like an only child. Children want to please the parent, so you did not fully realize the dysfunction you were taught to see as normal.

This desire to want your own needs met only to fail and give in has been engrained in you from an early age.

That is a hard thing to change as it means changing self. That means others will not like that you don’t give up and give in.