Well, they had hospitals and schools, mosques, homes, universities, a stadium, agriculture, water systems, electricity - all that will need to be replaced. Obviously not by Hamas as they shouldn’t be governing, should they? So should help these poor, traumatised, displaced people?
I would start with their neighbour and the country who caused the most harm to that infrastructure. Israel has flattened Gaza. Israel has cut off aid and then limited it. They say they are saving Palestinians from Hamas so why not feed them and help them rebuild the land they destroyed?