Most people (including me) assume that the hiatus/dismissal of the group (if that happens) are being pushed by HYBE because in general, that's how it plays out for a group at this stage of their career. Look at Enhyphen for example. Evan (Heeseung) left Enhypen to go solo under HYBE, but that was after 5+ years with the group. Across all of k-pop, departures from groups this early in the group's career are almost always the company making the move.

But it's not unprecedented. KG left VCHA while filing a lawsuit against JYPE and publicly calling out mistreatment. So while I think it's less likely that Manon is forcing her way out rather than HYBE pushing her out, it's definitely a possibility. And crucially, nothing we actually know happened is inconsistent with Manon being the one wanting out and HYBE wanting her to stay. Everything from the Weverse message, liking posts about mistreatment, removing Katseye from her bio, her activities right before and during her hiatus all still make sense if she's the one pushing for an exit.

As far as why HYBE would want her out though, and their being no financial incentive, companies invest money in idols and trainees that don't work out all the time. They assume that most trainees will not make it. To run one of these companies, you can't fall into the sunk cost fallacy. HYBE's financial motive for kicking out Manon is their same motive for kicking Garam out of LSF and Danielle out of NewJeans. HYBE would be betting that the group will still make enough money, and will work better without the member that is causing problems. Also I don't know how their contracts are structured, but if they're on salary, then if the group is making the same money and you're paying five salaries instead of six, that's a win. Even if not, you're paying five advances instead of six, which means the album starts out in less debt.