If you summoned an Ancient Artifact, you must put a Mystic Artifact into your EX area, and vice versa.
Not especially good, but it could be worse
Magic Online Society's website and Discord are good places to start down the player-run-events path, and Cardhoarder maintains a list of them as well, although I'm not sure all of the events listed are still active
Were going to see more of that
Battles are decided entirely by which Digimon uses the stronger attack with no other effects coming into play, the game ends when one player's deck is emptied, and whoever has won the most battles at that time wins the game
I mentioned a moment ago that Im less high on Path to Exile lately, especially in games with more tuned decks that arent the high end of the format