You can literally see Gaza City leveled on satellite maps, very few buildings are left standing. Even if Isreal hadn't killed a Single civilian, tens to hundreds of thousands would eventually die of exposure because they have nowhere else to go, their homes have been destroyed (Egypt isn't willing to take Gazan refugees and it seems like neither is anyone else in the area).

The infrastructural damage alone is enough to indirectly kill 10s of thousands minimum in the long run. And of course Isreal has been striking civilians, so the total scale of the civilian life lost will be much larger than that.