This is going to sounds basic but the point of war isn't to kill people. Killing people and destroying stuff is part of how you carry out war, in fact it's like a main feature that differentiates war from other forms of politics, but that's not the point of war. War is a political activity meant to achieve some set of ends, right? Like the enemy has stuff we want and they won't give it to us so we take it from them, as an example. There's diminishing returns on the ability to kill and destroy, in order to wage a successful war you absolutely need terrible force, but you also need to be able to do a lot of other stuff in order to make your objectives happen. So using our "we want stuff" example, you have to kill and destroy until the enemy isn't willing to stop you from getting the stuff anymore, but you also need to then have the logistics to actually get the stuff, you may need international recognition that the stuff *should* be yours, you might need access to markets for the stuff, etc. You can't win a war without objectives sort of by definition because there's no measure for success at that point.

What are the US objectives in Iran?