In 2012, during the Arab Spring, Palestinians(Hamas) was crossing the border from Gaza and causing problems in Egypt. So, over the course of a year the Egyptian army flooded 32 tunnels with sea water so stop Hamas from coming into their country.
The Syrians do not want them. They have enough refugees of their own.
What the Egyptians fear is that when Israel closes the net on Hamas in southern Gaza they will be overwelmned by refugees fleeing south into Egypt.
Perhaps they could wander around the Sinai for forty years?