I got stuck on the quest "all that glitters ..."

Long ago I got stuck in the mission “All that glitters …” in which you have to participate in a duel between two master blacksmiths Zach and Otta to obtain the information about the copper coins. It turns out that I chose Vitus’s father, but I lost and he refuses to give me any information and only insists that I repeat the duel (which the game does not allow me). I also tried choosing Otta and letting myself win, but I still have no information. I found in forums that if you lose one way or another, you will have to pay Vitus’s father to get information, but the blacksmith does not ask me for the money and keeps insisting that I win in a duel in which it cannot be repeated, so which is the whiting that I’m caught in a loop. I admit that I am quite bad with the sword, I get nervous and lose in the duel, but I would like to know if there is some way that I can avoid the duel or, even if I lose, continue the story.

Lockpick the shed in the back of Zach’s smithery. In there you will find a clue that will move the main quest forward.