https://www.bbc.co.uk/news/articles/cj41y42qxq8o
I think the problem with the below is the mammoth coast and the problem of who pays. To build a city of the size of Birmingham from scratch including public infrastructure to a sufficient standard using non slave Labour is going to be astronomical. Who pays? All the Arab states (although some with concentrated extreme wealth) have their own domestic pressures without stumping up hundreds of billions to produce a new sixth state. There could be international loans but that would bring into question Gazan public debt and how loans could be repaid.
There is also the thorny question about how Gazans go about establishing legal ownership of land or whether they need to buy it again. It seems like a conveyincing nightmare. One solution would be to build identical properties and allocate them the to the populace as a whole but would Gazans want this form of communism in terms of property? If you do have a housing market how do establish a realistic economy to support it?
International aid is extremely stressed and certainly as a UK tax payer I would hope we wouldn't get to involved and as Gazan reconstruction is talked about we should be conscious of the levels of poverty in other regions of the world.