countries never stopped trying to knock off heads of state or leaders. its just a matter of can they actually do it or not
Sure but when is the last time it actually happened and from a direct assault ?
Leaders killed or arrested in activity are usually from a coup or a rebellion by their own citizens. Now those coups may have foreign influence, sure, but the optics remain the same ie an internal conflict.
As far as I'm aware, a foreign country killing another head of state in times of "peace" is unheard of (there was no declaration of war and the US and Iran were actually in negotiation...). I think Japan killed the Filipino president but that was during WWII.
I'm not gonna be sad about the death of Khamenei at all. But let's not normalize the absolute lawlessness that has been happening lately with Maduro and Khamenei.