I recall the other plausible rrrrrrrrrrrat being that she had started hanging out with the Mean Girls of Cyberlive again. Some supporting evidence for this is a stream when Lumi talked about Yuri hanging out with the wrong(?) people (someone who knows can pull up the clip). There was also some look into her personality and I recall some people saying she'd be prone to submitting to such a clique and being a lackey.
Lumi didn't say she started hanging out with the wrong people, but that her and Yuri kind of drifted apart and Yuri started hanging out with another group (or something along those lines). It could have been the other Cyberlive girls, or it could have been Lia and Rie, who she had been collabing a lot with at the time. I'm pretty sure Lia called Yuri her best friend at the time or something like that, so I assumed Lumi meant them.
Whatever happened to lead to the falling out with Phase, it's under lock-and-key, and it'll probably always remain that way. Whatever it was, it involved a violation of her contract on her end, management trying to work with her to come to an agreement to fix the problem, and neither side coming to an agreement which lead to her termination. Whatever it was, nobody is willing to reveal any details, and the split was mutual enough for Phase to allow her to make a farewell message to her fans on her YT channel and she did just that. Though, the Phase girls have often been pretty awkward around any mention of her
I would also like to note that when the announcement was made, there was very little negative responses on this forum. Most of us her surprised, curious, and felt it was a shame to see. When the rrat of her taking private donations on a personal account started taking traction, among other rrats, most of us felt that whatever she did was a violation of her contract, and it was a dumb idea for her to do, but that it wasn't something malicious to actively harm anyone. Due to this, people expressed that the termination was deserved, but it was a shame that it happened in the first place because it was just a dumb decision on her part.
I think more of the negative reactions toward her started coming later, after the dust had settled, and I think started picking up more when she was discovered as Nano and she started vague posting a bunch. I could be a bit off on this, but I remember personally starting to get annoyed with the constant negative vague posting that she was doing after a while.
At the end of the day, the jokes, memes, and speculations will never stop. But as others have already brought up, most people here don't dislike her. We're just shit posters. I don't watch her content now, but I still do have fond memories of the good times she had when she was Yuri back in Phase. I still remember the fun streams she did with Lia and Rie, especially the stream she did with Lia about furries, and I still remember the fun times she had with Lumi. One of my favorite collab streams was the one she did with Lumi, Pippa, and Kirsche. With what we know about everything, I don't have anything against her and wish her the best moving forward. She seems to be doing fine, so she should focus on that.