Although it's not a starter deck, one of the best YuGiOh Master Duel decks is the Six Samurai. It's one of the more simple decks in YuGiOh, and will teach you about the summoning mechanics and how to swarm the playing field. This is because the deck largely revolves around putting out lots of low-level monsters to populate your side of the field, and then sacrificing them to summon more powerful cards.