Well first i didnt think this topic will get much attention here, thank you for your replies and answers. But to be specific i wanted like more of the games or matches where those player been caught and what was their punishment and who really found out about their bet
So, in general, athletes are not allowed to bet on themselves. There are a few exceptions to these rules, especially when athletes find grey areas in the legislation and regulation processes. This is only valid for individual matches and sports, like boxing, MMA, or tennis
As for this exception i think its with the fighters where they bet against each other for big amounts of money and the winner takes it all its more known in boxing matches, but they cant for bet on their loss because certainly it will be weird if both fighters do their best to lose the fight haha
You can search through search engines to find more results

If the player cannot bet for himself, he can ask his friend to place a bet on him so that he does not have to do anything that violates the rules.
So, there must be a player who told his friends to bet for that player so they could get more money.
And it wouldn't get him caught by the organizers or the authorities because there would be no evidence that he was betting on himself.