Why didn't AJ box the way he did against Usyk 2?

Probably because he has thug ego.
Dubious challenged his ego and so AJ wanted to punish him. It played into Dubious' hands.
Beating someone on points isn't punishing them it's just winning the sporting contest.
You have to remember that AJ is a thug at heart, groomed by Team GB and handlers to look like a 'decent guy' and 'sportsman'.
He's not.
So when Dubious came along the inner AJ thug came out and he wanted to be the big-dog drug dealer on the street corner, instead of doing the smart and calculated thing like say a Wlad or even Fury would do.

Problem is that AJ has power but he isn't tough for his size. The fact a non-HW and light puncher like Ruiz beat him up is pretty weird. AJ is actually huge and riddled with roid. The talk about AJ's chin needs to be put into perspective. It's not terrible overall but for his massive size it's pretty bad. Part of being a tough guy is being able to take damage.

 

Because his trainers were Boxercise Ben Davison and literally some random guy with a youtube channel.

 

I think it´s time to give Dubois his respect and stop calling him Dubious.

 

Coz he's a shot fighter. Stick a fork in him.