I had to work for years to get the piece of a rating I got. Just to have cheaters like him ruin it
80%winning percentage

Correct. But it enables a streak where you can win 80% of your games.

Magnus doesn't have it. Hilary doesn't it's not possible because the more games you win the harder people you play

If it’s not possible how’s [removed -- MS] doing it
Already been answered:
His account is fairly new, and sub 200 games isn't a lot. He likely is still climbing to his true strength and his rating hasn't stabilized yet. There's not a "way to increase your win ratio to 80%", it just doesn't work that way. Just focus on improving and playing your game.
He's also playing 30 minute games, so although it will take the same number of games for his rating to stabilise, those are going to take longer. And it will take longer before the 50/50 wins at his true rating level wash out the effect of all those early wins.
Just because someone says they're going to do something doesn't mean they're actually going to do it. If he's cheating, the fair play team will get him when they're certain, they never just leave cheaters alone, where do you get that dumb idea from?

If you feel like another member is using disallowed resources you should report them
https://support.chess.com/en/articles/8562517-how-do-i-report-someone
https://support.chess.com/article/648-what-do-i-need-to-know-about-fair-play-on-chess-com
https://www.chess.com/article/view/online-chess-cheating
https://www.chess.com/article/view/chesscom-update-july-2024#FairPlay
The site closed almost 60,000 accounts in June for fair play violations and has a full team of staff working on reports along with some automated systems for detection.
https://www.chess.com/article/view/fair-play
That said, discussions of cheating, potential cheating, or cheat detection are not allowed in the general forums. If you would like to discuss join the following club. https://www.chess.com/club/cheating-forum
Really look at his all time chart.