Could you please paraphrase the underlined part in the sentence below:
"You have overplayed your hand here. No one would call me successful.
It comes from the game of poker. In poker you are dealt cards and you keep them a secret from the other players. Then you bet on who has the best hand. The person who matches the bets and has the best hand wins the money. But if you do not want to match the bet you have to fold (give up playing that hand).
If you "overplay your hand" then you lose because you have overestimated the strength of your position relative to the other players.