Iran has been preparing for this for the last 50 years, half a century they have put into preparations. Their sole motto of existence was this war only. And it is not Iran alone Yemen, Russia, North Korea, China, Lebanon are on the same side. US has already deployed one third of it's military in the Gulf along with Israelis.
US still believes that they will social engineer the Iranian folks, but that is not feasible because the Iranian mullah regime has proven itself to be strong. Social engineering is only feasible where regime is already weak and plenty of access of social media. Once the mullah regime gets weaker then it is possible.
Secondly, you have a Ukraine factor in this. US is looking at two fronts. More over for a single weapon fired it costs US more than what it cost Iranians or Russians due to cheaper labor factor.
Americans need to either go in brute like in Normandy or Japan way.