I think you're putting too much weight on its intentions, it doesn't have intentions it is a mathematical model that is trained to give the most likely outcome.
In almost all examples and explanations it has seen from chess games, each player would be trying to win, so it is simply the most logical thing for it to make a winning move. So I wouldn't expect explicitly prompting it to win to improve its performance by much if at all.
The reverse would be interesting though, if you would prompt it to make losing/bad moves, would it be effective in doing so, and would the moves still be mostly legal? That might reveal a bit more about how much relies on concepts it's seen before.