How do we fix it? Israel shot themselves in the foot by keeping the Palestinians divided and ensuring that a two state solution can not be viable. Therefore, the UN needs to step in and implement a one state solution. Palestinians in Gaza and the West Bank would be given citizenship and representation in a combined state. UN peacekeeping forces would have to fight against groups of terrorists (both Hamas and Israeli) who oppose this solution.
Israel has the right to exist, but no one has an inherent right to an apartied ethno-state. The combined state would have a more equal amount of Jews and Arabs, so the Israelis would be unable to oppress the Palestinians the way they currently do.
Is this a popular solution? No. Will anyone seriously argue that a two state solution is still viable and that Israel will work towards that? No.
The idea of a Palestine controlled by the UN was actually part of the original plan for the region that the British drew up, before they decided to use the Zionists as a convenient tool to screw over the Arabs.
The current state of affairs weakens the entire idea of the United Nations as a tool for preventing major worldwide conflicts. If Israel continues to get away with ignoring international law, and if the US continues to veto UN resolutions that seek to hold Israel accountable, it contributes to moving the world closer to WW3.
People will say that the situation is much more complicated than just "European colonizers oppress yet another group of brown people". Fine, if that is true then that is a good reason why the US should not be taking one side over the other, and the US government should back out and let the UN do what needs to be done.