The way I think about this is somewhat novel I think.
Suppose we have two universes, everything the same, except one has free will and one doesn’t. Would an observer be able to tell them apart? I don’t think so. Maybe I just lack imagination, but I don’t see how free will would actually make a difference.
Your decisions determine what kind of person you are and what kind of person you are determines what decisions you make. They are self reinforcing and tied up together in a big path dependant knot.
Wanting to be a better person also only works if you let it change your decisions, bringing you one step closer to being a better person.