dont forget the destruction of Mecca, the Aswan high dam, as well as atomic detonations at strategic points into the country of Israel to stave of invading forces. I would also blast an area in the desert region on the Egyptian border as well. Tehran with 2H’s, Reactor sites at Bushehr, Arak, a strike on the purification sites at strategic locations associated near water at Gchine, Chalus, Neka, Tabriz, Lavizan, and Gorgan. Follow up with atomic detonations at every major port which supports military vessels. You have to go all in if you are attacked.
You are so right. There's no other way, because you can't be sure how much they've got left to hit you with.
NOT fully committing will only get more of your own people dead. It'd be like hitting the schoolyard bully twice your size with one shot, briefly knocking him down, but not finishing the fight then and there (while you can).
...and that's what's so scary about a nuclear war. It tends to ratchet UPwards rather than DOWNwards. It's self-escalating feature is pure evil genius, all the more so because it's so necessary.
Somewhere, The Devil is smiling.