Free Will has no Efficacy (If at all it exists)

There is a perennial debate on whether free will exists or not. Rather than going into the arguments about its existence, let's take a practical point of view. For a moment, keep aside the question of its existence and see if it really makes any difference if exists or it does not. We do not really know if everything in this world is predetermined. On the other hand, we also do not know if the world is just a random occurrence of events. But let's take both the cases and see if free will has any role to play in either case.

Case 1: The world is deterministic. Everything that has happened in the past and will happen in future is predetermined. Clearly, if everything happens according to predetermined things, free will is just an illusion. There is no free will that case.

Case2: The world is just a random occurrence of events where past events have no links to the future events. If that is the case, no matter what you do, the outcome is just going to be a random event. Even if you decide to do something consciously, it is not going to affect the outcome anyway. Therefore, even if free will exists, it has no efficacy.