Usyk had the harder cruiser run; Holy faced better heavies. That said, AJ stacks up in any era imho. If he beats Fury that's a big boost to his resume.
At Cruiserweight Usyk edges it although Qawi, De Leon, are up there with Usyk's best opponents at Cruiserweight. For Heavyweight it's no contest Holyfield clearly has a way better resume at Heavyweight, and beat names like Holmes, Foreman, Bowe, Tyson, Moorer, etc. But again it's not a really fair comparison because Usyk has only had a handful of fights at Heavyweight.
Foreman and Holmes were too old, Holy looked awful v Holmes, AJ is better than 90`s Foreman and Holmes.
Holmes and Foreman very still good fighters Holmes had recently schooled Mercer and Foreman went on to become Lineal champion. Foreman and Holmes are better than anyone on Usyk's resume outside of Joshua but a 90s Tyson is better than Joshua. Holyfield has a superior resume at Heavyweights that's obvious.
It should be taken into account that Holyfield's 190lbs cruiserweight and Usyk's 200lbs cruiserweight are not the same thing (today the differences in the smaller divisions are 3lbs).