How would you define free will first of all?
Second, how would you determine the difference between a universe in a simulation giving off the illusion of free will and true free will?
Third, how do you solve the problem of other minds? You can believe you have free will but why would you believe any other mind exists outside of your own mind and any other will exists outside of your will?

If you go based only on behavior then how do you distinguish between a sentient conscious being and a p-zombie?
Currently people consider AI to be p-zombies but at what point would it be considered sentient and conscious with free will?

Since we are made up of genetic code, is there a big difference between how we emerged and how an AI emerges? It could be that the universe is completely deterministic and our free will is merely an illusion. The illusion would come from the fact that time exists for the conscious and perhaps consciousness itself manifests the existence of time to allow for the illusion of free will but the actual universe may be a deterministic state machine where everything exists at all once.