Joshua throws straight and with speed and power - it's why he'd be a handful for Fury, and why he'd demolish Wilder.
However... Usyk is technically outstanding and he doesn't stay on the middle line basically ever. So for example, don't expect him to be smashed to bits like Pulev was with that overhand right.
That said, I think Usyk, over 12 rounds, is just too small and not a concussive puncher to keep Joshua off him, and Joshua is too good to allow himself to be boxed on the outside for 12 rounds. So I think either Joshua puts him to bed early, or puts him away when the pace slows around round 8.
The only way Usyk wins is if Joshua is stupid and fights at his pace and chases him round the ring, knackers himself out and Usyk pop shots him to a decision.
So Joshua inside 8, or Usyk has a shot on points if AJ gets his gameplan very wrong. Well, in a fair world anyway - in reality, Usyk needs to stop Joshua to win tonight, as we saw with that Campbell Hatton farce earlier.