Two hundred years ago, the vast majority of Palestine was Muslim, and most of the rest were Christian. Almost all of the Jewish population growth until 1948 was from European Jews.

The only legitimacy nations have since WW2 is the UN. As I keep pointing out, the tragedy of Israel is that it wants to play by 19th century rules in the 21st century.

If you look at a map of the war of 1948, you will see that all of the land grabs were by Zionists. Ben Gurion is on record as not planning to abide by partition, and Plan Dalet proves he meant it.

Israelis did not exist before the 1930s either. However, the region of Palestine has been known by that name since Herodotus's time, so its inhabitants would logically be called Palestinians.

Thanks to the OED, we know the name has been used in English for centuries:

1583 I am now constrayned to declare of the battaile that was begunne betweene the light of all knighthood and the furious Palestinian.

As for the antisemitism trick so often played by apologists for Netanyahu: https://comrademorlock.medium.com/why-zionists-love-identity-politics-b253c380da9c

And while I love the alternate universe game, we have no way to know what would have happened if Palestinians had not become the scapegoats for Nazi crimes. There's no reason not to assume there would be a Palestinian nation.