If you think about this in the quantum-mechanical framework, it appears to contradict this free-will problem. In relativity, reality is a solid block, and future events are as immutable as past (no free-will). But in QM this statement would be expressing a level of certainty which violates the measurement problem and Heisenberg's Uncertainty principle. In Penrose's recent book he posits an interesting hypothesis on the Big Bang based on this. Roughly... stuff in the observable universe appears to be slowing down, getting colder, and further away from each other. Things start hot and energetic, and slowly lose energy, slow down and disperse. So, taking this model of the universe and winding it back, you get to the Big Bang, when the universe was infinitely hot and dense. Winding the model forward, you eventually reach a state when the universe is infinitely cold and empty. This is the heat death of the universe, a state of oblivion where there is absolutely no interaction, and no stuff.

This violates Heisenberg, but QM is the map, not the territory, right? So maybe, in practice, reality has a way of beating Heisenberg? Thanks to technology, we have been able to probe this question quite recently. Scientist tried to create a near-perfect vacuum, with all the energy and stuff removed, and isolated from the rest of the universe. Inside the vacuum they created an electrical circuit fed to a computer. The circuit was broken by two floating polished plates, separated by an incredibly small gap, roughly the size of a short wavelength of light. So in this test chamber photons of all sizes could exist around the two plates, but between the plates only the smallest photons could fit. If any large photons enter the chamber they would create positive pressure around the plates, pushing them together, closing the circuit and registering a result. As the scientists pushed the vacuum closer and closer to a perfect vacuum, would Heisenberg get in the way? Maybe the experiment is not powerful enough to push the vacuum close enough to really challenge him?

The experiment was a success. As the vacuum increased, eventually large photons showed up outside of the plates and pushed them together. Photons where appearing out of thin air to ensure that no perfect vacuum could be attained. We call these Virtual Particles. They usually annihilate themselves before becoming "real" and observable, but if local conditions are just right, like near a black-hole, some virtual particles are lucky enough to get pulled and stretched, and this process lends them enough energy to materialize. The virtual particles are of course random, and this apparatus is actually used now to generate proper random values. You can actually tap in to the vacuum energy with an API to get your source of entropy!

https://en.wikipedia.org/wiki/Casimir_effect

Vacuum energy quantum RNG: https://qrng.anu.edu.au/

Back to Penrose... when the universe approaches this infinitely cold empty state, it turns out to be the same, mathematically, as the hot dense state. With everything being so distant and disconnected, the universe sort of forgets that it is big and empty. Then all it takes is the enough quantum fluctuations and virtual particles to appear in some small region of space, that they pull on each other and become real. This might, according to Penrose, trigger another Big Bang.

What does this have to do with relativity and free will? If it is true that nature, at the smallest level, is fundamentally random, then the block universe containing a predetermined future cannot be real. So free will is safe? Not quite. If the Andromeda people are anything like us, their brains are subject to same laws. The electrical activity in the firing synapses, that we call thinking, must also be subject to the random fluctuations of quantum mechanics. How can they have free will, when the electrical impulses driving that will are fundamentally random and unpredictable?

Weird, eh?