How do opponents of Open Theism address this:
God knows all things. But it is logically impossible to know in advance what a free will agent will choose. That cannot be known in advance because the free-will agent has not yet made his choice.
If someone knew (it doesn’t have to be God) that you were going to eat an apple tomorrow, then it would be impossible for you to refrain from eating an apple tomorrow. For if tomorrow you choose NOT to eat and apple that would indicate that that someone didn’t know after all.
By the way, when you look up the passage about God knowing the end from the beginning, it is clear that it is speaking of Him knowing the end from the beginning of his plans. In no way is the passage speaking about God knowing the end from the beginning of all events. That is but a presumption.