It really has no correlation with whether a vtuber’s a bitch or not. Pretty much every vtuber’s oshi is either Mori or Gura because they’re in Holomyth and Myth is what got them to become EN vtubers. They’re the closest to classical anime girl tropes (the cool one and the cute one). Kiara, Ame, and Ina all are way too niche to be an inspiration to an aspiring vtuber.
Also, Myth being so much bigger in numbers means the chances of collabing with them are next to zero. It would just be fucking weird if you said your oshi was someone who has similar numbers to you and that you could collab with anytime you wanted. Those are either friends or coworkers or both, not oshis.