Not sure if there is a specific answer, there are leaderboards for each variant
Bullet? The best player is Magnus
Blitz? The best player is Konevlad - I don't think Magnus plays blitz often.
Rapid? The best player is Drvitman, Magnus doesn't play rapid
Maybe Magnus, but we'll never know?
It can also depend on what variant you're talking about. Some players (like me) can be good at rapid, but can suck at bullet because they aren't used to the fast time control.
Soon enough, this will turn into a fight about who's the best, so we can leave it at this, without a 100% clear answer! I found this at
lichess.org/player which shows the leaderboard, so I'm not getting this out of thin air (of course). Maybe you can just look at that and get your answer for now, because this thread is completely useless especially its in Game Analysis. Put this in general chess discussion instead!
You may would like to read forum ettiquette before posting something random like this