I wouldn't be confident at all. Usyk couldn't stop Michael Hunter, who is a complete novice compared to either Wilder and Joshua. He clearly beat Briedis, but Usyk's lack of power was made obvious again. Usyk wouldn't be able to get either Wilder's or Joshua's respect with his lack of power.
My sentiments exactly. Joshua has at the least a modicum of skill and a grasp on the fundamentals to compliment his size advantage. He'll also be the huge A-side favourite with home advantage so any 50/50 round or reason to stop the fight will undoubtedly go his way. Wilder has none of these and was losing rounds to Szpilka, who is inferior to Usyk in pretty much every conceivable way.