She initially joined Big Hit as the chief brand officer, not Source Music. Likely with the intention she would be making a girl group at Big Hit. But then Bang told her they would buy labels and debut girl groups under those because BT$ fans are jealous teenagers. So then she started to plan out a group under Source Music which they had bought, but then he came in again and said we are debuting a girl group under Source Music with these IZ0NE girls. He thought she was going to agree to being in charge of that but it went against her vision, plus she was mad it would screw over the trainees at Source Music, it would effectively mean many of those, if not all of the NewJeans girls would not debut. So MHJ demanded her own label so she could carry on her original vision. She insists she only took Minji and that the other girls later joined the company via auditions (though I think she likely also took Hanni) regardless the amount of trainees she took should not have so severely bankrupted Source Music that they'd need to disband Gfriend, that was on them for being poorly managed to begin with.
As time passes she notices many little moments between her, the CEO, and Bang that suggest their relationship has soured and they are trying to sabotage her group in small ways. She was promised that her group would be the one to debut first but then they decide to debut their thrown together group first instead (and we know it truly was thrown together, Kazuha had only 6 months of training). Texts suggesting they want to use her to take down competitors and the biggest one being the text showing jealousy over NewJeans reaching Billboard before Le Sserafim. Reminder, it's clear Bang had promised LSFM big things considering those girls went on Knowing Brothers claiming one of their goals was getting a Grammy. Iirc they also had going to Coachella as a goal too.
Meanwhile, her group is growing and so is her label's value. It's known she has male trainees and potential plans for a boy group debut. So she starts looking into selling her shares which is where contract disputes begin as her shares haven't vested yet. Not only that but for 5% of them they also require Hybe's permission to sell. She starts working with lawyers to rework this contract cause she realizes how much it fucks her over. Despite her lawyers advising her not to do so, she sends in an internal complaint when ILLIT debuts and she can tell the concepts are way too similar and close to NewJeans comeback to simply be a coincidence. Hybe then retorts back demanding she resign and performs an internal audit. She goes haywire because resigning with the current contract she has effectively means being blacklisted from the k-pop industry.
Simply resigning does not make her shares disappear. With a non-compete clause she can not work anywhere else if she has the shares. Hybe claims they tried to renegotiate the 5% but did not state in their reply what the date for renegotiation would be, all we know is it's a later time than the 13% she can sell by Q4 this year. Right now, Hybe are working hard to try to prove she has done something illegal(this is why she brought up the whole company card thing during the press conference and that they'll only find her late night dinners on there), if they can do that then those shares would be relinquished and at a price lower than market value.
They have also been smearing her in various ways, like claiming she hasn't returned her laptop for audit when she states the date for her to return is different from everyone else. And then dropping the shaman meetup right as her press conference began, perhaps they thought she wouldn't be able to counter that so quickly hence the timing of it. After her press conference they initially said in their statement there was nothing of worth to respond to that she had said, but then later they decided to go through a bunch of points with their lawyer speak.
So in a way they are correct, this is about money, but moreso for Hybe than it is for her. For her, she is focused on if she can continue working in this industry or not.
Ig my only question would be why they would have given her so much power to begin with. It's clear from her time at SM that LSM was smart to never give her a role too big. You don't really give that type of stuff to the overly passionate, overly involved creative types. Especially someone like MHJ who lives vicariously through the idols she produces. We know she also gets offended on NewJeans behalf a lot. Such as that whole awards show fiasco where she was mad she won an award at a show but none of the members/group did. And it's so obvious when there is a scandal she's the one writing those huge defensive posts defending them (Cookie one).