TBH I seriously doubt Israel even alone couldn't handle Iran. I doubt Israel could 'take out' Iran, but:
Muslims make for the dumbest, most unreliable and ridiculous soldiers on the planet.
If Russia couldn't take Ukraine, a military that equaled them in the quality and design of their military equipment, then Iran isn't going to accomplish shit against Israel, when Iranian equipment is outrageously outdated and Israel has the best US money could buy. Iran has regularly posted absurd lies about their military capability. Anyone remember their "fifth generation fighter" that a person couldn't even fit in and just gets towed around because it's not a real plane and can't fly? If Russia couldn't get their asinine Su-57 working, Iran sure as hell isn't.
The fact that the Mossad has apparently so *thoroughly* infiltrated Iran means they had no trouble finding people who hate the ruling regime. HUMINT isn't a bunch of jews getting rhinoplasty, it's finding sympathetic assets willing to cooperate with them against their country.
And Iran has fuck-all for allies that aren't fair-weather at best. If Arabs refused to do anything about the Gaza situation, they sure as fuck aren't going to help fucking Iran. Russia sure isn't going to get involved either.
Iran has 10x the population, across a huge area. Israel 'taking over' Iran is impossible. But this kind of works the other way too because Iran is never going to get a land army to Israel either. Manpower doesn't matter when you're basically locked away from a hostile power you don't share a border with and your sea route goes past multiple countries who really just kind of *don't like you*.