I don't have all the details. Some of it is in her book but it's not in English. I think once she retires she will probably publish an English version and add some chapters to cover the last part of her career and experiences. She also has a planned podcast where she will be talking to other athletes about their experiences. She is very likely to talk about hers but sadly it's in Polish. I hope we get subtitles but it's highly unlikely.
From what I remember, just off the top of my head, back when she had no money one of her first coaches / gym owners ripped her and others off. I think she said that one almost made her quit. During her UFC time she had numerous problems with managers, which is why she and one of her sisters handled it for a while directly, but the worst was Perfecting Athletes.
We know by far the most about PA because several gyms had serious issues with this group of incompetent individuals. Nobody had it as bad as Joanna though because these people wormed themselves into her personal life and acted as her family, doing her laundry and acting as assistants, while she was in the US. It got to a point where they began to interfere with her S&C coaching. You might remember that the head of this company was the one that Pat Barry yelled at backstage at UFC 217 to get under Joanna's skin. These were people she made excuses for every time they failed her. They miss-handled her nutrition and cut vs KK, Andrade and Rose 1. The head of this company called herself a Doctor legally because apparently in Florida the laws are loose enough that an acupuncturist can call themselves that. That helped legitimize her despite her incompetence in nutrition and weight cutting.
The way PA wormed themselves into ATT in itself is interesting and a sadly common occurrence. They did it through networking not skill. First they made contact with this sports management company. They might have already convinced some fighters at that point to use them. ATT had a relationship with this sports management company and recommended incoming fighters to them. So when someone like Joanna came to the US and joined ATT she was pointed to this company who manages numerous big name UFC fighters. This company in turn recommended Perfecting Athletes to her, despite not doing due diligence on them which would have revealed them to be a fraud, and the rest is history.
As far as why PA is bad it should be enough if I simply told you that they handled the nutrition and cut for everyone the same. They didn't take any basic facts into consideration.
Post PA Joanna obviously continues to have problems with coaching and cornering. All you have to do is listen to her corner audio which is sometimes rage inducing poor. The only recent fight where it was decent was vs Tecia which she won. I don't know exactly what's wrong currently but she just spent 3 weeks with Ernesto Hoost who is very likely to be honest (critical) so hopefully she takes that to heart. I don't think all of her ATT coaches are bad. Obviously she is improving in some areas but in general there is a serious problem and she needs to address that or she will never wear gold again or if she does and doesn't fix this problem it will be despite them and not because of them.