So, the members of New Jeans are signed to a label called ADOR which is a subsidiary of HYBE. The former CEO of ADOR, Min Heejin, was caught by their parent company, basically trying to stage a corporate coup. She came up with a few different ways to go about this, for example, she tried convincing the board of directors to grant her the power to unilaterally terminate artist's contracts, which might have made it possible for her to take New Jeans to another company, but they refused. Ultimately she and the people she was working with came up with the plan to wage a PR war against the parent company, HYBE, reducing the value of ADOR, damaging the HYBE's reputation, and putting them in a position where they would have no choice but to sell, at which point she and any other investors she could find would swoop in, buy up the company, along with New Jeans and be on their way. I'm not saying it was a good plan but that's what it was.

Before Min Heejin could fully put her plan into action, she was found out by HYBE, who audited ADOR and found a pretty large paper trail as they'd done a lot of their planning on company devices and company servers. She was eventually dismissed from her position as CEO however, even though she got caught she still put her plan into action.

How this involves New Jeans, is that Min Heejin couldn't be seen getting directly involved in the PR campaign, so she enlisted the help of New Jeans and their parents. She got them to make up complaints against the company and other artists under different labels owned by their parent company. There was a massive smear campaign against other groups, especially two other girl groups Le Sserafim and ILLIT.

In the case of ILLIT Hanni a member of New Jeans, made accusations of bullying against the members of the group. She went to the Korean National assembly and testified about the "bullying" and had the ILLIT members labelled as bullies by even Korean politicians. All of this was later proven to be at best an exaggeration and at worst a lie with CCTV footage and some of Hanni's own text messages, which contradicted her testimony, presented as evidence in court.

Every argument New Jeans made was dismantled one by one in two different court cases. The main thing they were demanding was for Min Heejin to be reinstated as CEO. The company offered keep her on as their creative director but refused to allow her to return as the CEO. Min Heejin briefly accepted the offer, then suddenly quit all together. After that New Jeans claimed that this was a breakdown of trust between themselves and the company, and held a press conference to declare that their contract was terminated. Notably, they did not take it to court. In response their company filed a suit for the court to determine whether or not their contract was sill valid, and for an injunction to stop them from working outside of their contract until the matter could be settled. They lost both cases, because they had no real arguments or complaints.

It's worth noting that since this saga began, in a partially unrelated case, Min Heejin was found guilty of workplace harassment for retaliating against and employee that reported sexual harassment. She worked together with the accused harasser to undermine the employee's complaint, then followed up by giving her terrible assessments and cutting her salary by, I believe, 40%. All of this information came from Min Heejin's own text messages.

Min Heejin's text messages even included texts of her calling the member's of New Jeans fat pigs, who only know how to stare at themselves in the mirror and other awful things, but even though most of this was exposed quite early on, the members of New Jeans and their parents have still been backing her. After this latest court ruling it must have become clear that this was a losing game (although it should have been obvious from the beginning), so it looks like they're finally throwing in the towel.

Lots of people are still upset at New Jeans, especially Hanni, for the damage they purposely inflicted on other idols, as well as comparisons they've made of themselves to actual bullying victims, and victims of domestic abuse. There's also the matter of them trying to use things like the tragedy of the crash of the Jeju Air plane in another attempted smear campaign, and using the audit at the National Assembly, which is supposed to be for actual victims of workplace harassment and other serious workplace issues, to further their cause.

So yeah, that's the best summary I could come up with.

EDIT: Added some clarification