If your deck isn't consistently relevant by turn 3, it's not competitive
At Pro Tour March of the Machine in Minneapolis, Wizards of the Coast (WotC) finally revealed what the mechanic the Ring tempts you means from the upcoming The Lord of the Rings: Tales of Middle-earth Magic set
Graded Population Report: Hau #144 Visualize the distrbution of grades in the chart
Control decks can also be a problem, as one of the best ways to disrupt control, forcing them to play cards on their turn, is hard for Reanimator decks to do, meaning that sometimes it becomes a waiting game of baiting your control playing opponent into taking action before you do, but even that might be difficult as many control decks forms of removal do so by Exile, not destroying things
Basically, in a perfect world, we'll get Sanctum of Fruitful Harvest and Sanctum of Calm Waters going first, and maybe even Sanctum of All, and then Sanctum of Shattered Heights and Sanctum of Stone Fangs will come down to close out the game
And this is partially true since Evertale 2.0 launched, giving the entire game a rehaul on the gacha system to include characters