That depends what you mean by “Israel”. I don’t think it can be an exclusively Jewish ethnostate. That means excluding Palestinians who have equal claims to the territory and I don’t see how that can lead to anything but oppression and further cycles of violence.
But sure it can exist as a state. They just can’t do military occupation etc.
Oh, I didn’t mean totally lose support, I agree and that would suck. I meant lose support for the occupation and operations into Gaza. I see no problem defending Israel from an invasion same as I support Ukraine against Russia’s invasion and previously protested against the US’ various invasions and operations.