There are some endgame basics that new players need to learn, K&Q against K, K&R against K, K & 2 Bishops against K, how to catch a passed pawn and some others. These aren’t difficult to learn, and once you reach these basic positions you can expect your opponent to resign.

The reason for the advice to avoid end games is that the real end game contests happen with positions having a few more pawns or pieces. These positions can have a single not obvious winning move out of many alternatives. One false step can lead to a draw or loss instead of a win many moves later. Two almost identical positions can result in different outcomes even with perfect play.