Prime Usyk would be a cruiserweight so this is a solid fight weight class-wise. This is the kind of fight where there really isn't anything negative to say about either guy. I'm going with Louis. He has the power to do some damage while Usyk is less likely to hurt Louis. Usyk would have the footwork advantage but Louis will get to him enough to win the fight.
Back to the theoretical matchup ….. I still hate you. I’ll go the wuss way out and say it’s 50/50 ( Actually May very well be honestly ) then I don’t have to pick between IMO the best ever heavyweight and my current favorite heavyweight lol.
Given that Joe himself said that he would never, ever defend against a southpaw, I think it is safe to assume that Usyk wins this easily. I love Joe, but let's be real. He is a guy who gets knocked down by 5'8" fat guys and light heavies with chronically bored hands. He ain't beating Usyk.
Prime Louis was a great KO artist. I also think Jack Blackburn could build a great game plan for Usyk's style. Louis KO 8
Usyk is bigger, faster and has better footwork. No way Joe Louis could keep Usyk in comfortable range with his awful footwork. As far as stamina goes they're roughly equal. I would give the chin advantage to Usyk given that he hasn't been KOd by somebody weighing 190lb, dropped by a 5'8 fat guy or even dropped by anybody. Also, Usyk is a southpaw and Joe Louis said he would never defend against a southpaw due to one destroying him in his gym. I mean no disrespect to the real GOAT, but Usyk has him completely licked.
His best performance is either vs Gassiev or Huck. I'd say between 2016 and 2018 he was at the absolute height of his powers.