The Israelis want regime change—period. They think, probably correctly, that a secular and democratic Iran would be more interested in economic growth than ballistic missiles and nukes. Trump, on the other hand, has already lost interest in the democratic opposition; he probably realizes that true regime change requires an invasion and an occupation, so he wants to turn Iran over to a local equivalent of Delcy Rodriguez. That way, he can make a deal on missiles and nukes and then walk away.
Unfortunately, Trump concedes that he has already killed all of the potential Delcys, and things could actually get worse. Whoops! Now, what’s the plan, Stan?
Leaving Iran in ruins and in the hands of a more thuggish theocracy, and then cutting the grass at the behest of the Israelis, most likely.