Going to do a mass reply, but
@God's Strongest Dragoon remembered the fleshstreams.
I think the timelines matter a lot. Sinder had gotten close enough to Numi's Vtuber friend group that they went on a Ski trip in Feb 2024. Sinder was in a car with Bao & Numi for probably 6+ hours. Not long after that, Sinder had the "vtuber physics are real" moment at a convention.
This is peak catnip to her and it started the increase in her incline in most stats. There was another big event in August 2024 which I forget which, but it's noticeable on the charts.
But, then the Bao Cake stream happened.
This is almost certainly what started the targeting of Bao. Now it's moved from just Vtubing stuff to IRL as well. Bao is younger and in better shape than Sinder, so that's some peak Women Envy potential. Much of the Indie space was obsessed with Bao's ass for the next 6 months. In all of this, Fillian starts the Fansly infection. So Bao runs the fleshtubing into more direct whoring at the same time that Sinder was really gaining even more traction. But, that doesn't work to the envious mind of someone like Sinder. (The Silvervale thing seemed to have happened because of a OneGuy'ing from /vt/?)
The timeline context explains most of it. Sinder was popping off, Bao also had a popoff moment and her sights set on keeping Bao down because she felt threatened.
Lily finding out first probably makes sense. She's the savviest businesswoman of the entire Indie set, and it's not really close.
I can't find the exact date, but the Vcarb collab went up on
Sinder's vod channel on Feb 5th. Somewhere in that and Numi's concert in Amsterdam on March 15th, everything seems to have gotten rolling.