If you look at Fury's history, his past fights, you will not see that he wanted to appear weak, he is already assure of a win in the first fight against Wilder, until that last round wherein he got knock down and it was just a miracle that he was able to get up and finished the fight and then it ends in a controversial draw. In the second fight, he didn't look weak, and on the contrary he is the more aggressive between the two.
So we should throw that out of the window because I don't think that any fighter wanted to appear weak as his opponent will go and try to get your head off and we was almost upset by Francis. Definitely, Usyk said that he won't made that mistake and underestimate Fury because he look very different against Ngannou.
Does appearing weak imply that he didn't take the fight seriously? While the bout against Ngannou may not have been a championship fight, it was an official one. Losing would mean a blemish on Fury's record. Therefore, let's not assume he didn't train hard for Ngannou; that would be disrespectful to a UFC professional transitioning to boxing who came close to defeating Fury. We need to move past that and see how Fury matches up against Usyk. Personally, I still think Fury would come out on top, and I believe the public shares the same sentiment.