Kovalev might have some chin issues, but he has proven himself with better opposition; so I say about the same.
GGG is, he is better defensively than ppl give him credit for Kovalev was getting seriously tagged by bombs from Pascal
I also rewatched GGG vs Ishida, and saw how a relatively small middleweight like Golovkin turned off the lights to what is now man who competes and holds his own at heavyweight.
From what we have seen so far I'd say Kovalev. Kovalev has shown he is more than just power and offense he showed in the Hopkins fight he has boxing skills and an extra dimension.
And he took them That alone should tell you about his supposed weak chin If it wasnt for Beterbiev id say Kovalev - he fights a lot more catious than Gennady
GGG. I think he beats everyone in his weight class and I don't really give anyone a chance. At 175 I'd give Beterbiev a chance v Kovalev (although I'd pick Krusher)
Kovalev is fighting better fighters. And he has more killers in that division... Kov is the better fighter.
Fighters only look unbeatable when they haven't fought anybody great. Show me a fighter who continuously fought the best around, in their primes, and didn't look somewhat vulnerable.