If the outcome was predetermined in advance, no choice was made
Correct. And it would not be possible to know what's coming in the future were it not already written in stone.
You have defined a situation that allows you to believe both that God has omniscience including for the future, and that man has free will as well by simply saying that free will occurred during a predictable chain of events, perhaps between where the pitcher threw the ball and the batter either swung or took the pitch (no swing), where there was no freedom to choose and say that free will occurred there anyway. Those two simply aren't reconcilable, nor are you trying to explain how they can both be occurring - a known future and a free will decision occurring within it. You simply say it happened because apparently your faith has you believing both happened. Christianity requires that because it justifies its God's supernatural judgments and punishments on free will existing, and souls being held responsible for those choices.
But not in a deterministic world in which everything can be known by a good enough mind. What you have described is a world with no free will and simply said, yeah, free will happened in this human object just before it did what it was always known it would do. You're describing a deterministic world, where everything happens like a moon orbiting a planet orbiting a star in such a way that eclipses can be accurately predicted, and then declaring that the moon's path was due to free will because of a faith-based belief that it does. When it is pointed out to you that if the moon's motions were predictable, they weren't the choice of the moon, you insist that just because the moon did what it did doesn't mean it had to do that.
Well, yes it does, and that is how one knows that there are no choices possible - he can predict what will happen. This is what a deterministic world would look like - perfectly predictable in principle. Ask yourself what an indeterminate world would look like, one where the future could not even in principle, even by an omniscient God, be knowable.
What you're not recognizing here is that free will requires indeterminism, without which, it is only the illusion of free will, by which I mean the psychological experience of experiencing urges and desires that were generated neural circuits, delivered to the self, and then acted upon as if the self was the author and source of those urges rather than a passive recipient of them. Maybe the hypothalamus is telling you to seek water, so you do, and think that that is free will because you can imagine that you might not have taken that drink. You imagine that you just wanted to prove to yourself that you didn't have to choose to drink, and so didn't.
But if so, you fail to recognizer that this is just another passive act on your part, having received instructions from the cortex to not drink just yet, which was the stronger of contradictory desires, and thus prevailed as you passively were witness to two ideas that didn't come from your mind, but rather, was delivered to it, duking it out, thinking. That is what is meant by the illusion of free will - a deterministic process that feels like it starts in the head with a desire that was created like a God is said to create - ex nihilo - but was actually determined by the laws of neurology.
What you're trying to do is to merge two mutually exclusive ideas - determined and undetermined - into the same reality by fiat. If your scriptures said that somebody divine was married but was also a bachelor, I suspect you would be saying that that is possible with God, because you decide what is possible based on what you need to be possible rather than what reason allows (noncontradiction), and essentially say that that is the case, and if others say that what you claim is impossible, they're being arrogant and either obstinate or dishonest.
If God not only knew but God also predetermined everything that would ever happen (predestination) then it would be deterministic, but God's knowledge alone does not cause anything to happen.
God predetermining the future is not a requisite for a deterministic universe, just that that future be determinable now. Man predicts eclipses, but doesn't cause them. He couldn't predict them if they weren't predetermined, or if the heavenly bodies had free will. The two are mutually exclusive. In fact, if they did have free will, that would manifest as unpredictability. The would suddenly change paths or speeds because they felt like it at that moment. That they don't is how we know that they have no free will.
