It's a shame if chess.com tolerates this. This behaviour is extremely toxic. Smurfing is slightly better than cheating. To be honest, it's a form of cheating.
Smurfing in chess

Why chess.com dont have a report for smurfing?
I found a guy today. He has 3000 win and 200 lost. If he is not cheating he is a high elo player smurfing low elo players with non rated matches...
[public accusations not allowed -- MS]
He even beated several 2000+ elo players...
You can report, but an account that has always been low rated and primarily only plays unrated is something that may not be something against the rules.
https://support.chess.com/article/209-how-do-i-report-someone
Why chess.com dont have a report for smurfing?
I found a guy today. He has 3000 win and 200 lost. If he is not cheating he is a high elo player smurfing low elo players with non rated matches...
[public accusations not allowed -- MS]
He even beated several 2000+ elo players...