I mean, Yotsuha probably tried that in one of her runs, but vengeance doesn't work for Uichi's happiness unfortunately. If I had to guess, she was personally responsible for the sister being imprisoned in the one run where Uichi ends up alone with Yotsuha, but her mother is in a psychiatric ward...
This is probably the first time this happened, so we'll have to see how this ends in tragedy. Afterwards, Yotsuha will do several retries and hopefully get an inkling that the person messing with Uichi's life is also a time traveler (that is what it seems like imo).
From Grok:
"The evidence leans toward craniotomies typically spelling doom for a boxer's career, driven by lengthy recovery periods, medical recommendations for a one-year hiatus, and the sport's inherent brain injury risks. While guidelines exist, the lack of successful return cases and the...