Algieri was knocked down 6 times in one fight. Wilder and AJ are damaged goods. Doesn't take much to drop them anymore.
Algieri was fighting Pacquiao and didn’t get knocked out. Your second sentence is an argument for their durability when they were champions.
Honestly becoming a champion with a chin as dreadful as Enzo is kinda of a feat on top of being a champion. Because these dudes with poor chins know in the back of their mind they cant take to many heavy shots, if any. To get over that not only the physical hurdle but the mental hurdles as well is somewhat inspiring.