So you know the mating pattern which is a good start. You have to restrict the Kings movement with zugzwang stuff and force it towards the corner. I wouldn't worry about it...how many games have you played that have reached this ending? In 10's of thousands of games I have had this maybe once or twice.
How to master Bishop + Knight mate?
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I've under promoted in 4 games to get the bishop/knight ending. All in bullet. I managed to win 1 game.
I've seen this endgame "naturally" only once when I completely blundered a winning endgame and I traded down into a losing knight bishop endgame. I drew easily.
You just practice it. Over and over again.
I know how to do it but I haven't mastered it and likely won't because I don't practice enough to be able to do it quickly due to how often it happens. So if I do find myself in such a position and I have less than a minute on the clock I'm pretty sure I am going to draw it. But then again, if my opponent manages to take me to such an endgame with me having a few seconds on the clock it can be said he deserved the draw.
Now if it's your thing to be the greatest bishop and knight checkmater ever, maybe try setting the engine to a lower level so it won't make the best (in this case most resilient) moves, which might resemble more human (lower-rated) moves.
I can perform the mate vs engines because they play a certain way almost everytime.
Against human players, their moves are just random and I seldom get to trap their King in the opposite color corner to use the "W" method.