“Also it seems he was wrong about black holes? In the end, does he deserve being compared to the greats?”
Yeah?
Lots of the “greats” were not 100% dead-on correct on everything, but they advanced their fields significantly so that the next generation could build off of their breakthroughs.
Exactly so. Newton believed in alchemy and creationism, but that doesn't take away from his work in mathematics and physics.