How to get the best value out of gold and gems in MTG Arena?
Hall of Famer Frank Karsten wrote the definitive analysis for this.

The short version of it is, for beginners with &lt;44% win rate, play BO1 draft for gem entry and BO1 constructed for gold entry. For average players with 44-54% win rate, play Sealed for gem entry and either BO1 or BO3 constructed for gold entry. For veterans with >54% win rate, play BO3 draft for gem entry and BO3 constructed for gold entry.