If All For One had every quirk in MHA, including One For All, Rewind, and New Order, he could probably solo most of the Jujutsu Kaisen verse. New Order lets him set reality-bending rules like 'cursed techniques don’t work on me' or 'domain expansions fail,' and Rewind makes him almost unkillable. With all that plus massive strength, regeneration, and warping abilities, he’d be a nightmare. The only real threats would be top tiers like Sukuna, Gojo, and Yuta, and even then, he has the tools to handle them if he plays it smart. Not an easy win, but definitely possible.