Simply having honkai gakuen is already better.
I just wanted to ask what era or timeline this is in? , since Honkai Gakuen is divided into several, but the very rotisimos characters arriving at the multiversal
I think you have a very wrong interpration of HG2's power scale. And no, this doesn't belong to Era Zero or New Era (Kiana is Sirin aka K423 unlike HG2 where she's the OG Kiana)