There is no "ethnic cleansing" of Palestinians.
Pretty much a myth.
Yes, there was a war in 1948 - those Palestinians who ended up in Israeli territory became Israeli citizens, now "Arab-Israeli's" with citizenship.
Those who didn't and ended up conquered by the Jordanian Legion or Egyptian military, were annexed by the Jordanians & Egyptians.
Any Jews within territory conquered by the Jordanian Legion or Egyptians were forced to leave (yes, "Ethnic cleansed") eg those Jews living in the Old city of Jerusalem and what is the West Bank today eg the Jews of Hebron - massacred in 1929, 1933 and 1948 altogether fleeing)
Did the Jordanians make a Palestinian state ? No, they just left Palestinians to rot in refugee camps - built no infrastructure or anything to assist Palestinians. If anything, the Jordanians assisted in the massacre of Palestinians to protect the Monarchy rule.
Did Egyptians do anything to assist Palestinians - NO, again, left refugee camps in Gaza from 1948 - 1967 and did very little to build any infrastructure - just use the Palestinians as Paens to continue a conflict.
Israel did improve conditions in Gaza - quite radically in the 1980's with 100,000's of Palestinians employed within Israel leading to some 95% employment (5% unemployment) - and a booming economy attached to Israel (who do you think radically renovated and improved the hospital in Gaza - no it was not Egypt but Israel in the 1980's).
After Oslo and Israeli unilateral withdrawal, poor Palestinian decisions and self rule only lead to Hamas rule and a worse situation than even under Egyptian rule.
...and yes, not only were Palestinians refugees, but almost 1 million Jews fleeing persecution from Arab regimes becoming refugees in Israel (the Sephardi Jews) - thats more Jewish refugees than all the Palestinians in 1948, pretty much makes the story of Ethnic Cleansing a myth beyng a Myth. As for compensation - those Sephardi Jews lost assets in those Arab countries dwarfing any Palestinian losses by tens of billions of dollars, quite unfathomable sums, considering a large part of the middle class business were Jewish owned in places like Iraq, all confiscated by the Arab regimes (or in Iran some 95% of Jews forced to leave and likewise had their assets stolen).
Think of it like the partitioning of India and Pakistan. Some Arabs lost their homes in a war and ended up in Jordan, Lebanon, Egypt etc and Jews forced to leave numerous Arab countries and ending up in Israel - pretty much like a partitioning of the Ottoman Empires borders and populations after 1917.
Quite reasonable considering there was never a Palestinian country and the name "Palestine" was hardly even used pre-1917 British Mandate and the land was known as the Vilayet of Beirut - with quite different borders (as the name of the Vilayet suggests - extending into what is Lebanon today and Syria to the North East)