Obviously Israel shouldn't exist at all. It's not a diplomatically expedient thing to say, but it's the only real anti-colonialist answer because Israel is actively a colony. That doesn't mean expelling all the Jews from Palestine -- it might shock you to know there are non-Israeli Jews currently in Palestine -- but it does mean that the proper boarders for Palestine are restored and thus that there is no ethnostate (Jewish or otherwise). Recent additions to the Israeli colony (for they are always recruiting) can be sent back to their homelands. Many of them have been there long enough that they have no connection to those homelands anymore (including the more direct descendants of Holocaust survivors, etc.) and they can stay on the land that was Israel, but a lot of them are only there because they like the Jewish ethnostate thing and will therefore flee of their own will. That volume of people fleeing will probably incite still more to flee, but some will remain and they should be treated humanely and as equal citizens, prosecuting whatever crimes they committed but not being treated like subhumans the way that Israelis treated Palestinian prisoners.

The US is a much more difficult question because unlike Israelis being a minority compared to Palestinians, there are many more Euro-Americans, etc than there are Native Americans because the genocidal project of the US is much more complete. Inevitably some land, the land recently taken and some of the more useful land than what the Natives have been left with, should be returned to them, but obviously deporting all the Euros, etc. is neither viable nor productive, like how (to a much, much smaller extent) deporting all the Israelis is neither viable nor productive.

That said, separate from demographics and land rights, the US government absolutely shouldn't exist because it is terrorizing the world, including through proxies like Israel.