some cheaters play 2nd best moves that are still winning moves

some of them try to get as many blunders as they can while still winning the game

it's not enough to look for 0-0-0 games

This is a common problem in online chess.
But luckly you can play without cheaters OTB ;)

It's not safe there either. A phone can play better than a world champion.

yes but the amount of people who cheat is astronomicly low

Can you tell on here if someone you played was cheating ?

That is the hard part telling if they are cheating :/

How do u cheat on atomic?????

I know from my experience on chess.com for over a year what makes me suspicious, opponents quickly making moves that make me think for a long time again and again.
However that could be just because they are a lot better than me.

Larissbug, that's likely just because they had calculated that move in advance, so they could make it quickly when the time came.