It’s literally in the Israeli Constitution that all Jews and only Jews can be are Israeli Nationals (edit: all Jews are per the constitution Israeli nationals, which is why any Jew can just land on the Tel-Aviv airport and ask for and get Israeli nationality).

Non-Jews in Israel can only be Non-Jewish Israeli Citizens which is something different in that country and has fewer rights than a national (for example, they have to apply if they want to move to live in some places and can be refused).

So at its very core Israel is and has been from the start an Apartheid state.