Joshua can beat Usyk, that is possible but is it likely? As you said, some people said yes and some said no. One thing for sure is that Usyk will not go the same way as Ruiz did when he was focusing more on partying and having fun rather than train heavily with a view to defend his title against Joshua in the re-match.
But still, any experts will think that he is not enough for Fury, Usyk is not underrated anymore but if he wants to be line up to all the great heavyweights in the present generation, he needs to beat Fury and win decisively to Joshua again, many think that Joshua can come back and beat Usyk again just like he did to Andy Ruiz, the rematch is on now and Joshua and Usyk will be back in training, now the table is turned to Joshua he must prove that his career will continue and for Usyk to prove that he is lined up to great heavyweights.
He can beat him. I thought the first fight was closer than most people are making out. Even the bookies still had AJ the favourite after the fight whilst they were waiting for the judges score cards to come in, at least on the bookies I use. AJ is going to have to have a different game plan though. He's going to have to try go for a KO otherwise the same thing will probably happen and he'll get outboxed. AJ has all the stats on his side and is much bigger and in better athletic shape so he needs to use that to his advantage. Maybe he should take Fury up on his offer to train him for free. The rematch clause has been activated now so hopefully they can get the fight organised ASAP so we can see one of them fight Fury. Neither should trouble him too much I don't think.