That is incorrect.
Israel never annexed Gaza. It never tried to own the land or absorb it into Israel.
Egypt illegally occupied it from 1948 after capturing the territory in the Arab/Israeli war (started by the Arabs). An act of aggression.
Israel OCCUPIED it from 1967 after capturing it in the six day war in 1967 (started by the Arabs), then tried to give it back in 1979 as part of the Camp David Accords but Egypt refused to take it back. The Arab League didn’t do much about declaring it a Palestinian State from 1945 -1967. Under international law in 1967, territory temporarily captured in a defensive war is not an illegal occupation. The occupying entity cannot withdraw until a peace agreement is in place with the relevant previous government but there wasn’t one as Egypt illegally occupied Gaza up until 1967 and the Ottoman Empire and Mandate for Palestine was long gone. Israel relinquished Gaza to the Palestinians in 2005 removing all Jewish settlements and graves of their dead.
Not one Jewish person lives in Gaza but 2 million Arabs live in Israel. What do you make of that?
Gaza was never a sovereign State before 1948 as the Arabs declined to make it one when they had the offer in 1947 and started a war with Israel, on the day it declared itself a state ad it was legally entitled to, instead.
Before 1948 it was part of the Mandate for Palestine (geographical region) for the territories of Palestine and Transjordan, controlled and administered by the British who captured it in 1919 when it was part of the Ottoman Empire ruled by the Turks for the four previous centuries.
If you want to go back in history, 1919 was not that far behind 1948, so if anyone had a legitimate claim to the land, it’s probably the Turks but they’re pretty quiet. Wonder why?
Facts matter.