This is a major operation, but it’s not the big one. That’s the point. It’s showing an escalating sequence of incursions.-
The intent is to fully show off the military capabilities. It’s performative war to serve as a deterrence against Iran, who are perceived to be the longtime rival. Israel has many countries who purchase military systems from them, and this is basically a major marketing event as well.
The immediate goals for this war are to rescue the hostages and eradicate Hamas as an organization. At a minimum, the senior leadership will be killed. Israel believes the senior leadership are in the tunnel system under Shifa hospital, but I suspect this operation is a raid on one of the tunnel systems closer to the border. Tunnel systems are a hard nut to crack. It’s too easy to defend them, so it’s a matter of cutting off escape routes and ventilation and forcing them to come out. Any alternative is simply terrifying - water, chemical weapons, or actually going down and fighting room to room with booby traps and worse.