It is impossible think to defeat the opponent just using "mill sources", you have to think to some alternatives: you can do that with a lot of order, and you must not need luck in order to win , every hand should be the ideal hand
Oketra the True is a fine card for the deck, but I like pretty much all the other four-mana cards better, so it gets the boot
Spells your opponents cast that target Sphinx of New Prahv cost more to cast
There are a couple other theories floating around though
The cost-reduction ability of Korvold, Gleeful Glutton doesn't change its mana cost or mana value, only the total cost you pay
Magikarp Coloring Page Magikarp swims through a lively underwater scene filled with seaweed, bubbles, a seashell, and a small fish