False statement, untrue. Brook has a granite chin, he was never even close to going down in Carson Jones so I don't know what that has to do with his chin. Have you even seen that fight or are you just regurgitating what you have seen on this forum? Brook also didn't drop vs GGG, the highest KO ratio at MW and he took big shots. Whether you feel GGG's power is overated or not, Canelo has been fighting welterweights most of his career. This combined with the fact that his last 3 fights have been farcical jokes doesn't do him any favours.
You have every right to question ggg power. Regardless his power can be minimized if you have defense decent enough not to take a pounding ie not B-list bum level. He doesn't have that highest tier one punch power like some were pretending. Anybody with the determination of a good boxer shouldn't have a problem with ggg.