So just allow Hitler to take over europe and make an ethnostate through mass exodus?

If you're talking about the nukes, I agree, they were unnecessary as Axis Japan was already on the decline.

But to argue the entire war was preventable by just displacing jewish people is naive and borders on antisemitic.

There might've been ways to prevent the war from starting, like not destroying Germany's economy as a scapegoat for WW1 would have done a lot.

But after the Nazis siezed power there's nothing you could do to diplomacy the Nazis into being peaceful.