>>109006976She never wanted to leave. She was pushed to do it after being put on a carousel of stalkers. 2021 Niji was able to deal with each of them individually, but weren't able to implement a permanent solution due to a weak legal department and/or Japanese lawscape. The threats eventually became really serious and she felt really bad every time she had to go on hiatus while Niji dealt with the stalkers, so she left to deal with it as her real self.
Since then, the legal side of things must've become robust enough for Lulu to think she'd be fine now.
Also, during her time as an indie, she was seen owning Niji merch, so there certainly weren't any hard feelings on her side. She also remained close to her Niji friends. I'm not sure the ungraduation would've even happened if it weren't for Lize tethering her to the company.