Teferi TwistThis deck is a Mill deck with a transitional sideboard to turn into Azorius Control on its heel to trip up people sideboarding againsy our game one plan.
This deck functions like a hard control deck. If you're playing against aggro, it's better to deal with early game threats with our removal or dig gor more, while against control we need to slam as many mill enchantments as we can early as to keep them from being countered. Finally, against midrange, since they have pieces to kill our enchantments, we want one or two pieces down early and then hold the rest while we play our game in case they wipe our enchantment package on board.
Midgame is pretty streamlined. If we have enchantment pieces down, we just play our draw spells at the end of their turn if we didn't have to defend ourselves. If not, put some down with enough mana up to protect ourselves.
Finally, in the endgame, we can storm off and easily remove up to thirty cards from their deck in one turn if we've been grinding correctly. If things are tight, drop the remaining enchantments and start going off.
Teferi isn't incredible game one, but our opponents don't realize that. Feign defending him and your opponent will waste valuable resources trying to destroy him buying us two or three turns on average which is too much to give us and be successful. I can't stress this enough, game one Teferi is mediocre for us, don't die on that hill, but game two he becomes our only win condition so play him cautiously.
After game one, when people put in their enchantment removal or Gaea's Blessings, take out
Drowned Secrets and
Psychic Corrosion first and then add in your sideboard from there. Our deck can already go late even against aggro decks, so put in whatever seems best for the matchup. More removal against fast creature decks, more counters against control or Drakes. Pretty self explanatory.
I've had a lot of success with this build on arena. With several times finishing Constructed ladders, this deck has bad matchups but never a matchup with zero play. This deck requires practice, but I believe it's worth it if you're willing to put in the effort. Have fun and happy milling.