Povetkin has a solid build with a lot of mass and bone density for his height. He also uses good technique to transfer all that weight into his punches.
He therefore creates a lit of force on all his punches, and has very high level power on his best shots.
He's a heavyweight GGG.
Wilder is a heavyweight Tommy Hearns. Not everything is hurtful because he doesn't have the body mass, style, or bone density to put weight on all his shots.
However, his top level power is crazy. This is because he can generate a lot of force, speed, and snap on his punches due to his long, "light-weight", levers, and the explosivness from his high muscle-fibre ratio.