I agree that Hearns stops him. But I don't think there's any doubt that Floyd is an ATG, H2H or any other way you choose to define it.
You act like Oskee wasn't awesome in his prime. Oskee would give a lot of the old timers absolute fits with his speed power and jab alone. Mayweather takes a bit to find his rhythm, that's just how his ring mentality works but that doesn't mean he is in there struggling with these guys. Maidana outweighed him by what, 15 pounds? Maidana would give a lot of the old 147 guys trouble with a 15 pound weight advantage, too.
At Superfeatherweight I think he's top 5 of all time, maybe higher. LW, SLW, WW..................I think it gets a bit more difficult to place him at that absolute highest. Who I recognize at GOATS are pretty much set in stone. He's up there at all 3 though but at SFW it's beyond a shadow of a doubt IMO.
If you think Maidana gives Leonard, Hearns, Duran a tough fight, then I can't take you seriously at all.
Floyd does not have any performance whatsoever above 140 that makes me think he could beat the top 5 all time welterweights. He just doesn't.
130-135 no one ever beats him. 140 is not a lock, but I wouldn't favor anyone over him based on skill and other boxing abilities (quickness, reflexes, power...) Not Duran, not Leonard. Robinson was 1,80 (same height as DlH) but shorter reach. I know it's heresy, but if you put a gun to my head I'd pick Floyd. I am a believer in sports evolution. Paul Williams and Thomas Hearns should win due to size alone, but I wouldn't be surprised if Floyd Usyk'd them.
At superwelter, the sample is too small IMHO. He has always looked extremely good, keeping quickness and cardio, but eye test can be deceptive. TL;DR I got him as H2H winner vs anyone from 130-140, with a reasonable doubt vs freaks with 5-6" reach advantage like Hearns or Paul Williams.
Floyd ducked so many fights that his resume is actually paper thin, like Canelo's post GGG, which Floyd even admitted multiple times. What makes you think Floyd has a chance against proven great fighters when he almost never proved greatness himself. The fight against Pac, which he ducked for over 5 years, saw Pac doing most of the damage while Floyd's pillow punch and hug technique with referee, judges and commentators on side to give him a "glorious" win. If that's the best he can do against a well past prime Pac, a guy like Duran would tear him a new hole. Floyd could not even beat Paul Williams prime for prime, and he knew it, which was why he went for the duck. Floyd's greatest skill was matchmaking.