I know theres a lot of "it was the joos!" Out there but hear me out. This one lines up nicely.
Background - Russia has long propped up the Iranian regime as a counter to US/Israel in the region.
Premise - Israel had to neutralize Russias long range strike capabilities before risking a war on Iran.
Tactics - both attacks used infiltration and local drone assembly/attacks. Both totally novel and never seen before in close succession. Timng and tactics indicate the same origin.
Outcome - remaining capabilities moved to far east. Southbound ordinance would have to cross China, which is diplomatically touchy. Reduces but doesn't remove threat to Ukraine.
QED
I definitely accept that inability-to-square, and while it's clear that Israel as good intelligence, I do wonder if they were just arrogant. It isn't the first time Israel got cocky and paid dearly for it. Not to mention that in the west we get a lot of Israeli propaganda that will try to make the Mossad look more competent than they are.
I could easily imagine "Hamas can't do shit to us" or "Even if Hamas does shit to us, we'll beat them back in no time" being uttered by very important people at exactly the wrong time and place.