I've had this exact experiences except I'm ENFP and my mother is ISFP.
Being raised to embrace the "hedonistic" part of life. Therefore not having learned any life skills because she only lives by the day (and sticks her head in the sand regarding anything that's uncomfortable to do/think about that is beneficial in the long run). Now being in my mid-twenties having to teach myself basic life stuff because she never did. Being 11 yrs old and having to tell my mom that "she can't ask me if she should get a divorce from my (abusive) dad because that's a deciscion that only she could make and also it's not fair of her to ask her child this".
The resentment you carry towards her weakness I relate to strongly. I shut myself off emotionally when I lived at home because I despised her and everything she did so much. I didn't realise I was a sunny extrovert who actually enjoyed interacting with people until I'd moved away from home. Until then I'd just been busy trying to be the opposite of everything she was, being this cold, nihilistic and emotionally shut of person constantly at war with my own feminity. In my mind my mother was eqvivalent with womanhood, and everything about it was BAD...
In my case it derives from my mother being abused as a child. This made her into a mentally unhealthy individual who leaned on me to much, looking for a friend/parent/comforter/security in her child instead of the other way around. And instead of taking responsibility for herself. I was and still am terribly co-addicted to my mother.
Have you read up about codependency? If not, do so, I think you could benefit from it. Even it your upbringing maybe weren't as "bad" as mine?
As a cunclusion, your mothers incompetence as a parent has nothing to do with her MBTI. It was she as a individual who was lacking and her dysfunctionality was expressed in a certain way due to her being an ENFP. Had she been an ISTJ she would still have been lacking but in a diffrent way.
It's great that you are looking for connection with other people with similar experiences imo! I just found it a bit ironic that I related to everything you wrote even though I'm the ENFP in my family. Clearly there must be other factors that weigh in on your mothers behaviour. Although I do realise that it must have been extra traumatizing for an INTJ child to have a emotinally unhealthy ENFP as a parent.