Yes, hammas leaders over the years were assasinated by mossad. Including just a month or so ago. Top leader Ismayil Haniya was assasinated by the mossad on Iranian Soil. Gaza is a whole different story. Though mossad is involved there as well. You cannot just go to Gaza and pretend you are gazan. There are so small subtleties as to be “gazan” that can be picked right away by any local. Its a small community where everyone knows everyone. Mostaarvim, which is a special unit of the police in Israel specializes on exactly that. Pretending to be arab gazan or arab west bank and conduct operations there. And they have presumably rescued hostages and assassinated specific hammas people. You might as well consider them a specialized unit of the mossad if you will.

Waging war on Gaza is to a. Put pressure to rescue the hostages and b. To eradicate Hammas on its people, infrastructure and weapons. So that OCT 7 will never happen again. You cant use Mossad operations to do that. You Do that with actual war and shit.