Heavyweight succession if Sullivan draws the hair color line, starting in 1882?

Starting in 1882, Sullivan fixes upon a wider, but different, range of superficial physical traits to exclude from the heavyweight championship. Sullivan will now only defend his title against brown-haired men. Blond, red-headed, and black haired men are all excluded from contention. Gray hair is also unacceptable in large amounts. Pink hair dye is right out.

Every subsequent champion follows in Sullivan's footsteps. The hair color line continues until the present day.

Assume that the heavyweight contenders and champs we all are familiar with somehow survive the butterfly effects of this change.

Who would have achieved heavyweight GOAT status under these conditions?

 

Since the hair color line affirmatively demands brown hair (rather than merely the absence of other hair colors), baldness will not be a workaround.

 

Fitz is screwed in this timeline, yes.