Lol looking at the translation, the chapter sounds completely differently and makes more sense
> It's implied Psykorochi became that strong due to absorbing part of Saitama's power
> Psykorochi is portrayed out of Tatsumaki's league and it seems she was aware of it
So based on that then, this fusion is probably just a temporarily boost. I'm assuming it will get stopped by something / someone, either due to Psykos failing to control Orochi or it getting interrupted by outside power cancelling the fusion
It also shows that reading the raw and reading a chapter in English can change one's perspective completely