Iran needs to fire almost everything it has at Israel at the start. Then while Israel burns, reach out to the U.S., tell them Israel was our enemy. We have dealt with them. We do not wish to get into a war with you. We are willing to fully cooperate to de-escalate, we will give up enrichment. We want to normalize relations.
Iran has the capacity to devastate Israel. It just doesn't go that far because they fear the U.S. will get involved. It needs to deliver a knockout blow to Israel early on.
Just look at them. Even with their state of the art weapons, the ballistic missile attacks wreaked havoc on their society; people running around screaming, fighting to get into shelters.
If we launch a 1000 missile salvo early on and overwhelm their air defences, then reach out to the U.S., I think Trump would sit this one out, or launch some symbolic strike with a few B2s and call it a day.
Netanyahu is getting weaker by the day. I think Trump knows.