Fury would have to do 2 things and I am not convinced he WILL do those things.
1) take his conditioning properly serious for a long camp if not 2 camps, like a 8 week conditioning boot camp, 2-4 weeks light (if time allows adjust all this as needed) then a proper HARD 10 weeks fight camp.
It still won't close the gap on Usyk having stayed in shape his whole life, but it would help BIG TIME.
2) Fight coming forward. Even if it means risking getting caught, but be smart about it, feint, switch it up, move his feet, all that shit.
He has to be the bull, he can't be the matador. He has to fight like the Wilder 2nd fight. If he has that dog still in him, which he might not.
While I belive he CAN do these things, I do not believe he will do these things.
If Tyson doesn't do that, something similar, or get a little lucky, Usyk can simply be himself and win again. Usyk has better skills, better cardio and should have confidence coming off a win and near stoppage.