So you have him behind the top 3 fighters who have ruled the heavyweight division for a long time. Most posters have him ranked in the top 4/5. That isn't being overhyped. I think he gives the top fighters a good fight even if he loses. That's better than watching Fury fight Wach.
I think only Wilder could knock out Joyce. AJ has a chance to stun him momentarily though which might make Joyce take a round or two off
I didn't actually know AJ beat him by KO in the amateurs. I know they have sparred before. Can't remember who got the better in sparring.
Joyce is the third best fighter so far, right after Fury and Usyk, and he is not overestimated at all.