KBN vs. KR generally is a draw except when one side imminently loses material.
With pawns on both sides it is more complicated. If there is an opposing pawn on the color of the bishop, then B+N can attack that pawn twice, while the rook can only defend it once.
what is a better endgame a knight and a bishop or a rook?
With black to move it is a draw e.g. ...Bg8;
with white to move it is a win because of imminent loss of material Re7+.

Im pretty sure it's a draw if there's just a knight or a bishop left, while you can produce checkmate with a single rook and the king
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