It wasnt a failure. Let me explain why its you who is deluded.
1) Iran warned its neighbours and the US was informed as well 72hrs before they carried out the attack. This means they wanted to limit damage and casualties as they knew Israel would have a number of countries rushing to defend it. Israel and allies had 72hrs prepare their defences.
2)The slow drones and some of the typed of missiles used were meant to be intercepted, per above point.
3) Irans objective was to hit the israeli bases which carried out the attack on their embassy. They succeeded, all the ABMs used failed in stopping those missiles regardless of how much damage they did, they showed they can hit the most defended airspace in the world.
4) Iran reestablished its minimum deterrence and redline. The size of this attack was more for optics and to show the capability to swarm. They could have used better/faster drones and missiles and given no notice, refer back to point 1.
So if you fail to realise the bigger picture geopolitically whats going on, one can not help you any more.