The Irish fight for independence can be very briefly summarised as: there was guerilla war, combined with / causing collapse of state function for about 2 years. During that time, the Irish forces successfully killed or forced out the British. Many people who considered themselves to be British either went back to Britain, or retreated to the north into what is now Northern Ireland. By 1921, Ireland was an independent nation. Some Catholics from Northern Ireland moved to the Republic but many stayed in their homes. The British people who fled for the most part could not return to their old homes or move anywhere else in the Republic of Ireland and live safely as citizens. They mostly lived as British citizens somewhere in the UK. The border eventually stabilised, fighting ended, eventually a peace agreement was signed and today there are 2 states in the land.
Today, there is not a significant lobby in Ireland protesting to give the British people who fled to Northern Ireland or the UK their ancestor’s land back, offer them citizenship or indeed destroy the state of Ireland in order to return it to the British people whose ancestors once lived there. In contrast, there is a very loud protest movement calling on Israelis to give the Arabs who fled to Jordan their ancestor’s land back, offer them citizenship or completely destroy the state of Israel to make a Palestinian state “from the river to the sea”. Ireland’s struggle for independence echoes Israel’s at every step, but in Ireland no one advocates returning property to the old occupiers but they expect Israelis to. That is a double standard.
A very brief summary of the history of Israel would be: Jewish people lived in Israel, the Romans came, caused a lot of death and suffering (equivalent: Irish people lived in Ireland, the British came, caused a lot of death and suffering) and took many of the locals to Europe as slaves. The remaining locals stayed in their largely irrelevant corner of the empire when the Roman Empire morphed into the Byzantine Empire. Then the locals (normal working people) stayed when the Byzantines (the political elite) were forced out by the first Caliphate during the Arab Conquests. (This doesn’t change that Israel is still rightfully the home of the Jews, any more than France “stealing” Ireland from the British would have made Ireland less Irish).
There were several different Caliphates, none of which had its capital in Jerusalem or anywhere which is now Israel or Palestine, so it continued to be a fairly unimportant corner of the world as wars continued and it was “owned” by several caliphates. There was massive population transfer during the following centuries and the Arab population and Arabised local population soon outnumbered the Jewish local population. (Maybe if the British had colonised Ireland more, forcing them to become Protestant or making them the minority in Ireland, then the Irish would recognise their “right” to Ireland today?!) This also caused additional deaths and suffering for the locals. At this stage, the majority of the Jews are still in exile, although mostly no longer slaves.
In the 1500s, the Ottoman Empire emerged victorious. The Jews from other parts of the Ottoman Empire moved / were moved to Israel, as were a lot of other people. Mostly these other people were not considered to be immigrants at the time because they were other citizens of Transjordan who were moving internally within their country. But using today's borders, they would mostly be Jordanians and some Syrians. There was also immigration from Egypt of both Arabs and Bedouins who were understood to be immigrants at the time. After the First World War, Britain “acquired” Transjordan from Turkey.
Shortly before the British left, the majority of Transjordan became independent. The very small Jewish population of the independent Transjordan was moved to the remaining British part. When the British finally left, the borders for the last remaining part of British Transjordan had been agreed and to avoid forcing more people to move, the land was split largely by religion into Israel and Palestine. This would have created 2 very weirdly shaped countries which would have struggled to function independently without very close sharing of resources. Neither could have defended its borders against the other.
The day the British forces left, the fledgling Palestinian state was assisted by the Syrian, Lebanese, Iraqi, Tranjordanian, Egyptian and Sudanese armies to attempt to wipe Israel off of the map and kill all the Jews. Luckily they failed. The reality was that the 2 states could never have functioned, so Israel became a more sensible, defendable shape. To do that, many people were expelled from their homes and fled to Jordan (mostly) and Egypt. Some were also internally displaced within Palestine, hence why there have been refugee camps for Palestinians in Gaza for 3 generations. They’re Palestinains from places which would have been part of Palestine had the British map ever actually become a reality (which it didn't becase the Palestinians rejected it and chose to start a war instead). The Palestinains from Gaza have kept them in refugee camps all this time, rather than letting them live in normal homes. This would be the equivalent of having a refugee camp in Northern Ireland for British people whose families once occupied Dublin (i.e. Palestinan refugees in Gaza), and further refugee camps in England for them (i.e. Palestinian refugees in Jordan). It sounds outrageous when we think of it in European terms, and it is equally outrageous in the Middle East. That doesn't mean the solution is to destroy the world's only Jewish state though.