Jeskai Flashback: If you're playing the Commander 2019 decks straight out of the box, it means that Sevinne, the Chronoclasm is your commander, and I (as well as the community at large, based on our preview rankings) think it's the worst of the face commanders in Commander 2019 by a pretty significant margin
As previously mentioned, taking a break from pumping out four to five creatures with various enter and dies triggers to pay three to four mana for an engine just grinds things to a halt
Fortunately, there are ways to cheat, like playing many changelings or cards like Arcane Adaptation to make everybody in your deck a doctor
In Commander, because of how many good cards have low mana values and your life total of 40, its much easier to make Ad Nauseam work
Sac two creaturesideally tokens or ones with death triggersand bring back any creature from your graveyard right to the battlefield