Yes, those are BJJ specialists. Conor is more of a stand up fighter. Just because he doesn’t prefer the ground doesn’t mean he’s garbage there.
BJJ is not just about submissions. Its your defense, its your body control, its your timing, its the way you cut angles etc….
Im about a year away from my purple belt. The brown belts mop the floor with me as they should….2 of them are 60. If you’re at a legit school, your belt is legit. Conor’s BJJ coach is Dillon Danis, one of the best in the world. If you’re a brown belt under him, you’re legit.
https://www.bjjee.com/articles/gilbert-burns-conor-mcgregors-jiu-jitsu-is-very-underrated/