They both fought Wlad, their best opponent perhaps. Definitely AJs. Fury did it first though. Wilder for me is better than anything else AJ has faced, especially in terms of the danger of the fight and the risk involved, and Fury fought him 3 times. Everybody wanted AJ vs Wilder a few years ago, yet as soon as Fury schooled him he was suddenly average etc. Yet AJ wouldn't fight him at the time. You'll probably claim Wilder ducked AJ, but I don't see why Wilder would have ducked AJ when he fought the better fighter in Fury 3 times, getting beat up a couple of times. Besides AJ has pretty much admitted it because the $50m apparently didn't make sense.
I think Usyk is a more difficult fight than Wilder. Wilder is more dangerous but there are a lot more chances to win against him.
Did AJ duck Wilder or was it the other way around? I have no idea. All I would say is to your point of Wilder taking the Fury fight, he thought Fury was finished as did most people. That's why he took it. He fought him in the rematches because what else was he supposed to do?
To me if you look at Usyk and Wilder as about levelling out and then look at Wlad being on both it's pretty much tied.
Then look at the rest of their resumes and it's not even remotely close. Ruiz, Povetkin, Parker, Takam and Whyte.
I'm not saying it's a hall of fame worthy list as it certainly isn't but when you look at who Fury's fought it looks like a murderers row.
This fight against someone who's literally never boxed before is the cherry on the cake though. I was defending Fury on here years before her returned and getting pelters for it but this is just a step too far for me.