>>88714009It's possible that it was one of the impulses that got her to reconsider. She talked about her lack of confidence/motivation about her music with Polka in mid-2022 in their now privated SCHOOL OF LOCK aftertalk zatsudan. I summarized it and we talked about here at the time:
https://warosu.org/vt/thread/25910389#p26103386To me, she didn't appear to be in the mindset to apply for a sololive back then at all, but who knows how the exact timeline fell into place. It always seemed to me that this conversation with Polka helped her get over her mental barrier a little, so it's not impossible she applied for a sololive after making up her mind about taking her music more seriously a while later.
Looking back at what she said back then, I'm pretty proud of her. She has become a lot more proactive about planning her own projects and has put a lot of effort into releasing covers and original songs and now even has an album of her own coming up. It's pretty obvious she is still struggling with these confidence issues, but she no longer seems to let it hold her back as much. Definitely looking forward to whatever she will announce on Monday, and to her eventual sololive as well.