Why are you trying to play King vs. King end games?
endgame: KIng vs king, bishop and knight

Force the king to a corner square of the same colour as your bishop by using your king and 2 minor pieces to restrict it.

I made the best blog ever on this subject, check it out if you want to master Bishop and Knight mate.
https://www.chess.com/blog/robbie_1969/endgame-essentials-bishop-and-knight-mate
Why so difficult.
What is the main line to focus on?