Here's the stats for both men. Wow. Prime Ali 6'3 205lbs 78'' reach, birthday January 17th. Prime Usyk 6'3 205lbs 78" reach, birthday January 17th.
Considering the HW division was about the same size as the modern CW division for most of Ali's reign, you could also favorably compare many of their best wins, if one was so inclined. Really though, how many "Usyk v historical great" threads do we need? This is the second Ali v Usyk thread of the day. And what it really comes down to as much as anything is are you A a classicist who believes the old ATGs are unrivaled and skills have diminished over the years or B a modernist who believe that boxing is just like all sports with tangible records, and has seen an increase in performance. 90% of posters basically fall into one category or the other, although there is a bit of overlap and inconsistencies.
Nobody beats prime mid-1960s Ali. Nobody. The guy was practically unbeatable before his hiatus from the sport with that combination of size, speed footwork and ring IQ.