If Iran had carried out a preemptive strike, it would have undergone a far worse fate than it is currently. The US and Israelis have been restrained in this conflict, despite what you see on social media.
Iran is already suffering the "Iraqi" fate from the 1990s, which is de facto "no fly zone". Meaning, the Imperial Forces can bomb Iran whenever they want, at least once a year (2025, 2026), then again next year and then again in 2028, etc, if the Iranian government doesn't fall this year. That is what they did to Iraq and Syria. Bleed them out, bomb them directly or indirectly. So in the case of Iraq, they invaded 23 years ago after Iraq was suffering brutal sanctions and "no fly zone" with bombing here and there for at least 10 to 12 years prior to the brutal invasion.
Iran will soon not have anything to fire back if the Imperial Forces establish air supremacy, meaning they can bomb any city and town in Iran whilst Iran has barely anything to fire back. We are already on that path, and we have Iraq, Libya, Syria - and partially Yemen as examples.
DPRK would have smoked these pro-Imperial cucks if they tried to threaten to kill Kim or any of his family and high-ranking staff.
If you know an air battle or an air attack is coming, there is no point to sit and wait for those pro-Imperial planes to reach your capital (or anywhere near it).
Whilst Iran doesn't have the capacity to hold off all pro-Epstein aircraft, you still don't need to sit and wait for "all of them" (F-15, F-35 and F-22) to come to "your" capital and to other similar cities. One should seek to minimize the number of aircraft that can penetrate the airspace and the easiest way to do that is then they are on the ground and NOT in the air.
Even attacking transports or refuelling aircraft would have been maybe even better, simply the logistics part of the coming attack before it happens. And ammo depots as well.