If there is an unbroken chain of causality, that means that history has been written start to finish already, and my consciousness is just along for the ride. The thing is, my consciousness is locked to right now, which is a single point in this 4-D space, as are all the consciousnesses that I interact with because that’s exactly what right now is.
Until the day I interact with a consciousness that is experiencing a different point in 4-D space other than right now, it does not matter if free will truly exists because from my perspective and from all of my scientific testing so far (like deciding to pick my nose as I just did), evidence suggests that my consciousness is capable of making decisions. Even if those decisions are all a result of a deterministic path, my consciousness felt like it made them so it might as well have.
citation needed