Well, you can play “who started it” to no end, but technically direct country-to-country assault started with Iran’s missile barrage on Israel.
Now of-course this was preceded by the killing of IRGC members in Syria (and some by beeper casualties in Lebanon), but they were there handling Hezbollah attacks on Israel.
Are you referring to the start of the 12 Day War here? If so, are you leaving out Israel's unprovoked airstrikes on Iran out of ignorance or dishonesty?
Now of-course this was preceded by the killing of IRGC members in Syria (and some by beeper casualties in Lebanon), but they were there handling Hezbollah attacks on Israel.