Another issue is that unless and until Hamas is removed from power, no real reconstruction can commence.
Let's look at this article.
How Long Will It Take and How Much Will It Cost to Rebuild Gaza?
Time said:
And it's unclear when — or even if — much will be rebuilt.
The agreement for a phased ceasefire and the release of hostages held by Hamas-led militants does not say who will govern Gaza after the war, or whether Israel and Egypt will lift a blockade limiting the movement of people and goods that they imposed when Hamas seized power in 2007.
The United Nations says that it could take more than 350 years to rebuild if the blockade remains.
There is no question that the so-called "blockade" must be maintained as long as Hamas (or a similar terror entity ) is in power. Building materials such as steel and concrete would otherwise be redirected toward rebuilding the tunnel infrastructure, rockets and similar.
Before anything can be rebuilt, the rubble must be removed — a staggering task in itself.
The U.N. estimates that the war has littered Gaza with over 50 million tons of rubble — roughly 12 times the size of the Great Pyramid of Giza. With over 100 trucks working full time, it would take over 15 years to clear the rubble away, and there is little open space in the narrow coastal territory that is home to some 2.3 million Palestinians.
15 years is clearly too long. Make it ~2,000 trucks, plus ~1,000 backhoes and ~10,000 workers (providing much needed jobs) and it can be done in 9 months, give or take. But that necessitates being able to deliver this equipment and much investment, which will likely not happen (and neither should it) while Hamas is in power.
Lack of open space is not the issue. Even before the war, most of Gaza population was concentrated in the built up areas, with much open space surrounding it. And 50M tons would not take a prohibitive amount of space. If we assume average density of about 2,500 kg/m
3 for the rubble, this would come out to 20M m
3. If they pile the rubble to a height of 10m, that is a 2x1 km rectangle.
Given that this rotten ceasefire keeps Hamas in power, none of this will happen. What I think is likely to happen instead is that individual families will start rebuilding themselves, fixing the damaged shells of their buildings or building ad hoc structures as best they can repurposing the rubble as building materials. That is dangerous, since there are toxic chemicals and unexploded ordinance in the rubble, but it is what it is.