Who currently has the record in boxing? My pick would be Usyk not only was he very dominant in one of if not the greatest CW eras ever he then went up to beat AJ at nearly 35.
Maybe Clenelo in terms of depth as he's fought 18 world champions IIRC but that's in 60 fights. Loma has fought a staggering 11 in just 18 fights and unlike many of his worshipped contemporaries who are rarely the smaller man he's routinely giving away huge physical advantages and also unlike them he's also fought a lot of big punchers and KO punchers, and many who are big/huge punchers his size or way bigger than him and are very big punchers for his third division and one he doesn't belong in. Usyk and Roman too
Usyk Canelo Choc Donaire Spence Estrada Jermell Charlo Josh Taylor Beterbiev Inoue Briedis Lomachenko All the guys above have been unified or undisputed and fought either everybody within a division or willing to fight anybody..
I'll take Usyk because he fought everyone in their backyard with unfavourable conditions. Canelo has some good names but he had close decisions and always tries to get every advantage possible
Usyk. Cleaned out a strong cruiserweight division then went up to HW and won the title in his third fight. All away from home in the other fighter's backyard too.