As Eurasians, they are definitely among the best boxers of all time. Both were dominant in their weight class. Who has better resume, cATG?
Bivol easy, had Turki been around when GGG was in his prime he would be just as good though. I think Bivol, GGG and Beterviev in their primes could fight any ATG.
Maybe would have been different if GGG had gotten the correct decisions in the 1st two Canelo fights (maybe Alvarez would never have even fought Bivol if GGG had 2 wins against him??) Official resume, it's clearly Bivol - even with the Canelo victories, GGG has nothing aside from Canelo like the 2 Beterbiev encounters to elevate his resume. His victories againts Jacobs and Dev were also close and somewhat disputed, Bivol has nothing remotely close aside from the Beterbiev fights.
Did you forget that Bivol not only fought Canelo, but unlike GGG, managed to beat him? Who do you consider the better opponent, Beterbiev or Canelo? GGG went 0/3 against Canelo while Bivol went 1/1. Though GGG fought a much better, much younger version of Canelo twice who was in better shape and fighting closer to his natural weight. GGG fought a very different Canelo the first two times from the Canelo Bivol fought, in weight, style, and overall condition. One key difference is the amount of bouts each guy has. GGG has twenty more fights than Bivol currently has, GGG has a lot more KOs. And to your point, GGG has been in "more" high level fights against elite (or near-elite) fighters you could say. But if Bivol goes on to fight Beterbiev again, then Benavidez, and then Canelo again then Bivol will have more big fights than GGG had. But as it stands, the poll stands at Bivol 19, GGG 1. And I think this all comes down to the fact that Bivol has accomplished something GGG never had, becoming Undisputed. Maybe if you asked this question a week ago more would vote GGG. The more big fights Bivol is in and the more big wins he gets the stronger the argument that his resume is better than GGG's. But 20 less fights is still 20 less fights.
Bivol by far Now had Sturm, Martinez and cotto nutted up and fought him his resume would look a lot better