This highest level ”thing” should be evaluated surface wise. I doubt djokovic has the highest level on grass. Someone there has 8 majors on that surface alone. Same on clay. The difference in the Number of majors between him and title leaders on those surfaces are way to big for him to even have an argument.
Fast HC? NO! Federer has 5 USO and truckloads of Cincy titles vs 2 and 0.
Slow HC? probably! I say probably because there’s only one title difference between him and the next best thing. *hiding from
@Hitman *
Number of titles at every major should decide which player has the highest level on every surface.
Consistency doesn’t equal peak level but, you can argue that even when not playing at their absolute best, the consistent player is able to win.