The issue is a tangled mush.

For one thing, "free will" is an oxymoron, given the premise of will is to affect and without cause, there is no effect.

The problem is relating the expression of will with predetermination.

Predetermination is flawed, because the act of determination can only occur as the present.

The future simply has not been fully computed.

The premise implies some omniscient omniscience, given it would require knowing all potential input prior to events occurring. Which would require this computational process to occur at least faster than the speed of light, though effectively instantaneously and universally.

Yet knowledge is inherently subjective. Signal from the noise requires a frame of reference, a preceding map or model, to interact. Otherwise it is not only just noise, energy flashing about, but that too much information and it also reverts to noise. Whiteout.

Now we are driven by our emotions, this essence of sentience, bubbling up, focused as the mind, with the intellect, the resulting forms of perceptions and collected thoughts, as little more than referee. Which desires to prioritize.

One usual argument against free will being that our neural processes are not in immediate control of our motor functions. Which if it was a valid argument, would mean that flies have more free will than people, given their reaction times are much faster.

The function of all our cognitive hardware is to process information, so that future reactions are better informed.

Which, given the shape of the world, still has far to go.