“But if Iranians are celebrating the murder of their Supreme Leader, then perhaps it wasn't an entirely bad thing.”
Not just that, there must have been people in Iran helping Israel/the US to get him in the first place, possibly even within the Revolutionary Guard. Who knows, we certainly won’t know everything.
The “Iranian people” will be as divided as we are here about the Tories/Labour/Green/Reform etc and the US is about Trump and this war itself.
We can sit here speculating and thinking Trump went for it because he got away with it in Venezuela and is gambling, but none of us actually know what is going on and what is real and what is not and what is purposefully faked or not. We do not even know what US may already have agreed with China or Russia or India or not agreed etc etc.