The document doesn't really say anything we didn't already know or couldn't reasonably speculate.
I've been saying from Day 1 that all the privated streams Zaion had must have been at least partially because her manager failed their due diligence of establishing what was not allowed (live scrolling through twitter due to faces, for example) and so punishing her would have been unfair.
On top of this, hiring a Genshin/FFXIV streamer and robbing her of her Genshin/FFXIV account is a bigger deal than not letting Selen use her old Apex account, because Selen can get back into Master/Pred lobbies in a few hours, whereas Zaion's accounts took years and lots of money to build. There needs to be a shift in policy there.
Either way, I don't think it's all of EN management as many of them speak of their staff positively, but whoever was handling Zaion needs firing (if we are to assume she's telling the truth). It doesn't undo the fact that Zaion wasn't helping herself throughout, though.
I maintain that removing her was probably still the correct decision. Every company has a brand, and while questioning the hiring of someone who has always made 'dark' jokes is valid - as is a much larger question about the sterilisation of corporate V-Tubers in pursuit of appeasing the Western crowd for overseas expansion - it's still ultimately their decision to remove her for, among other things, not adhering to that image.
However, I also feel NijiEN fans should be pressuring the company into a higher quality of management. Though a lot of recent JP trips no doubt point to the resumed work on the 3D Live, it doesn't undo the fact that a logistical clusterfuck made them cancel it only 10 days after announcement. The livers deserve better regardless of your opinions on their content.
There's little doubt in my mind, though, that this kind of thing is happening in every JP corpo. I'm sure Vesper is reading that Google Doc with some empathy, and there was that one clip of Kronii saying her manager was shit at communicating with her and doing their job. There was that one time HoloID were strong-armed into making an ID-friendly schedule by management, and we had to sit in discomfort as Risu quietly seethed live on stream for 2 hours.
Production Kawaii is a train wreck of awkward textbook GFE, and there was that time the now-graduated Aletta Sky - a girl who sounded like she was from London - had to convince her fans she didn't interact with men after Alban showed up in her chat, despite London having as many men within a 100m radius as a small country. I'm not sure what people here think of me, but I can say that working under Japanese corporate autism as an outspoken Westard was the career equivalent of a guided tour through Pyongyang.
All this is to say that NijiEN and HoloEN have about 50 members who have at least tolerated management since debut. One person being completely incompatible with the work culture isn't indicative of the management quality overall, but Sayu's comments do warrant investigation into the actions of her handler around that time. If they are still there, then existing and future members could suddenly run into problems.