I think AJ should win this comfortably, though Dubois did have a great performance against Hrgovic. I just think AJ is too good for Dubois and Dubois is known to eat a lot of shots and I'm not sure he'll survive AJ's ones. Hopefully the winner of this fight fights the winner of the Usyk/Fury rematch, though no doubt if Fury does manage to win they'll then make a trilogy out of that, though I don't expect Fury to win unless there's some controversy.
But during first half of the fight, Dubois looked good against Usyk. What is he tries to go all in and tries to finish AJ early? Dubois is good at fight starts, but as a one-punch-knockout-boxer, he isnt great at late rounds. Frankly, I dont see Dubois winning this. And even if he wins, the next opponent most like will beat him, as he supposed to be a level higher than AJ.
As for the Joshua-Dubois fight, it is a very good chance for both to rise in the rankings, and most importantly, to earn big money.
If AJ wins, imho he will stay on the same level. Dubois hold only interim IBF belt. On the boxrec, AJ is still higher in rankings than Dubois. AJ will only get money and +1 win.