This a good suggestion why aren’t they doing it?
Even in wartime, Israel’s government is fractured. They would be slow to reach consensus and agreement on a plan as I suggest due in part to the continuing suffering of Israel’s own victims of October 7 and the diversion of resources from the war effort. Israel also no doubt wants international support and approval for any camp building. My guess is nevertheless that something like what I suggest is in the discussion and planning stages.