You may not be able to literally select which cards are going to the graveyard with each discard spell, but by paying attention to what cards your opponent keeps and what they give up, you can try and time your punches to cut off their decisions and paralyze even the most powerful Constructed decks
Azorius Oculus Out: 4 Archfiend of the Dross, 4 Unholy Annex, 1 Cut Down In: 2 Dreams of Steel and Oil, 2 Negate, 1 Ghost Vacuum, 1 Anoint with Affliction, 1 Withering Torment, 1 Jace, 1 Deadly Cover-Up This is a slightly favorable matchup.In general, your expensive Demons are a liability against Soul Partition and Into the Flood Maw
Arceus VMAX is a great card to allow you to find the cards you need, and Duraludon VMAX really appreciates that since it's better the earlier you play it
in other cases, when a creature is put onto the battlefield attacking, that creature's controller chooses which player or planeswalker it's attacking
If you do, put your choice of a +1/+1, first strike, or trample counter on that creature
If this card is Special Summoned from the GY - this turn, your monsters cannot be destroyed by battle So battle protection for all monsters you control for that turn