Looks like things are now starting to develop.
The Usyk team have known for a while that Joshua wasn't keen on the rematch. They've desperately been trying to make the undisputed fight with Fury but either Fury or/and his team haven't seemed keen.
Fury's preferred option is Robert Helenius or Manuel Charr. But it's difficult to see that being credible. I suspect what might happen is that the Fury team will refuse step aside money for Joshua and Whyte (to allow Usyk v Fury) so he'll end up fighting Whyte. That's as long as Whyte doesn't pursue legal action for a bigger % of the split. A similar scenario happened when Fury was supposed to be fighting Joshua. That fight was ready to go, but the Fury team refused a deal where Wilder got step aside money. That meant Fury avoided Joshua and got to fight Wilder again. Wilder would have accepted the step aside and a shot at the winner. Of course he would, he'd have been fighting for the undisputed for more money plus with step aside already banked.
The above scenario would probably leave Usyk in limbo as Joshua definitely doesn't want the rematch at the moment. The rematch could get made, but he'd probably pull out with an injury.
The person who has to be very careful in all of this is Usyk. He's the real champion and wants to fight the best out there for all the belts. Fury, Joshua and Whyte are all playing games to a certain extent. They've all got issues and insecurities.
Of course, there is a chance Fury might take the Usyk fight if the there's no other option. But Fury can't beat Usyk, so it's difficult to see it happening next.