I could also see a timeline where Elira was working with the circumstances, i.e. main branch didn't give 2 shits about the EN sidebranch, hence the lack of proper management which brought in complaints from newer livers.
But while they would (probably naively) say that the issue should be raised with NijiJP management and get more managers and staff, Elira would get frustrated because she knows that JP management does not give half a shit. And the more the livers whined (without helping her do management work) the more resentment would build.
Newer livers would be right normally, because yes, management IS supposed to do a lot of the work Elira is doing. But what should "ideally" happen is often not what happens in reality.
And obviously thanks to doing all the work she had less time to stream, hence a lot of her peers overtook her - and all she could see is them whining about management, not helping out one bit, and maybe deciding "you know what, I can't stream enough to get money, I should at least get more merch as compensation".
And then that little spark of darkness just grew and grew until she became what she is now.