Here's the thing. We can say what we want, but I think it's pretty certain that Fury is "mentally unstable" to say the least. Yeah, at the moment he's motivated to the max, who wouldn't be? But the first thing he needs to do is lose 7 stone! And in the right way without weakening himself would be a bonus. Factor in the possibility of injuries because he's trying to get back too quick. This is a very possible scenario.
Then , he needs to blow off the cobwebs. Anywhere along the line, he might go off the rails . This would then further put him back.
I'm not sure that someone as mentally unstable as him can be that disciplined......again! He was for the Wlad fight , mentally and physically, and look what it took out of him.
If Fury was as he was against Wlad, and AJ was also, I reckon AJ might just catch up with him. Styles make fights and he led Wlad a merry dance, but I'm not sure that'll be enough for 12 rounds against a Joshua, who age wise is in his prime.
Not sure they will ever both be at their peaks though.