That crazy puzzle leaderboard.

https://www.chess.com/leaderboard/tactics

Currently there are 11 people at 65540. I think that’s the max you could get.

Interestingly most of these players are shooting from 1100 rating to 40,000, 50,000 etc in a matter of a few days. They are also solving a lot of these puzzles in under 3 seconds, which for most people is absurd. The accuracy of passing is also super high. I know Hikaru will sometimes do puzzle streams, and even he doesn't beat them as fast as these players are. Safe to say that the top 100+ people are most likely not true to their real strength as a player.

I am sure some cheat. There are many low rated players near the top.

Why is that?

Cause you're not affecting any other player's rating
Fyi,chess.com doesn't ban you for cheating in casual games(I think)