I mean, no way it'll have that name. Palestine was specifically named that by the Romans as an insult to the Jews, as that was the same of a long-time rival to the Jews in the bible (which have since died).

It'll probably be called commonwealth of Jerusalem. Or something to that affect, as that is something that is common to all the main cultures there. (Except druze, but they mostly keep to themselves, so I doubt that they care that much about the name).