I think I know the answer but just trying to get more definitive. It's been difficult for me to see the difference. It seems to be the same ideology at the end of the day. The only difference seems to be that Zionism (most forms) stay localized rather than claim racial superiority for the whole world. But maybe not?
It seems like the fascists tried to speedrun the US’s success as a rival imperialist while Israel is simply an extension of the US’s power using the same settler colonialism. While the fascists were ambitious and trying to revive an imperialist past, the Zionists have less history to rely on and are simply an extension of existing imperialism rather than trying to rival it. That’s just some random analysis of the differences. They are largely similar, but other people have better reasons they are different.