Having not seen many of Usyk's fights, I went to BoxRec and saw where there is no mention of him even being down in a fight and the only damage listed was a cut over the right eye in the first AJ fight.
At 6' 3" and averaging 221 lbs. his last 2 fights, I'd say he's on fairly equal footing with Wilder who is 6' 7" tall and should come in around 215-220. His biggest obstacle will be Wilders 5" reach advantage, but that is only 1" longer than AJ's 82" reach and he handed that well in both their fights. Then add to that AJ is a much better technical boxer than Wilder.
It will be interesting and I give Usyk a real good shot to win.