I might be way off here, but I think joshua might be thinking along the lines of, he's already beat parker, parker beat wilder easily, and fury was knocked down 4 times by wilder in 3 fights, and hit quite easily at times by a guy that can't box that well.
Joshua made mincemeat of wallin, who pushed fury extremely hard for the 1st half of their fight , and in a lot of people's view should've won the fight by stoppage due to the gash he opened above fury's right eye.
And after watching fury against ngannou, is probably thinking the same as a lot of us, fury is on his way down.