Well if there’s just one thing wrong in my wall of text, so be it. Googling around, it looks like Egypt is the group that doesn’t want the Rafah crossing opened, because they don’t want Palestinians settling permanently in their land. And Israel has been bombing the crossing and the migrants at it.
Concentrating Palestinians who were already in one of the most densely populated areas of the world into what, half their original land mass, is pretty genocidal on its own. Maybe just no longer doing the genocide. They could stop.