Palestinians were indeed forcefully displaced in a region where they have spent decades, if not centuries, living in. While it is true that Jews used to live in the same place nearly 2 millenia ago, they were cast out by Romans and more or less permanently displaced before the time of nation-states.
But it is not Jews' fault that they needed a national home or a nation-state of their own, they were facing persecution in wherever they went for seemingly unfounded reasons. The problem was the Balfour Declaration and the promises and bargaining terms with Arab leaders around WWI period where the Brits over promised themselves, the French, the Arabs, and the Jews for a piece of land that the Arab-Palestinians were already living on.
For the Palestinians, it is hard to constantly live in an environment where you were displaced without thinking your homeland was overtaken by foreign invaders, therefore it makes it harder to establish a state. Furthermore, having two separate enclaves in the West Bank and Gaza Strip, it would be nigh impossible to effectively govern a state where its lands are not connected.
For the Jews, on the other hand, they would feel they won back their ancestry homeland and took back Jerusalem. They would feel they won the struggle and redeemed themselves as the "chosen people". And in an effort to defend themselves in order to not lose again, like in the first century CE, they just retaliate against any military aggression from their neighbours. You call it aggression, they call it self-defence.
The UN and the major global powers struggled to provide a good and clear solution for both sides to settle, let alone live in peace. One of their proposed solutions made Israel-Palestine look like a mismatched jigsaw puzzle.
And then the hostility of Arab states didn't help Palestinians either. They want the Jews out of Israel-Palestine entirely, therefore they would not want BOTH to settle down. They only want Palestinians to settle down. So, instead of helping the Palestinians, their aggression against Israel made Palestinians' lives worse. Their actions ultimately forced Israel to be even more aggressive towards Palestinians, with heavier blockade and retaliation.