All prophetic fulfillment requires God’s have ultimate sovereignty and control over human hearts. If an Arminian says God can promise to do something in the future (and not merely foretell it like a fortune teller), then God has to be able to overcome “free will”.
Why? All human events, whether wars, births, marriages, migrations, etc…. involve humans choices. If God wanted Israel to defeat another nation, or if he assures that he will save all nations, or says he will send the Messiah, all these things require simple human decisions like, a king deciding to fight and use such-and-such a strategy, various men and women having sex so as to make sure a descendant of David is born (Jesus), and that people actually go to all nations to share the good news. These are promises of God.
If God is not ultimately decisive over human decisions, God cannot actually DO these things, thus can’t promise them. He can only predict them. This is not the sort of God we see in Scripture. That kind of thinking inches closer and closer to deism, if it is not indeed deism. All Christians believe God gives promises, not merely predictions
If you believe in prophecy, you must inevitably accept God’s sovereignty over individual wills, which thus leads us to accept the doctrine of individual election.