With my (very) limited understanding of physics, I couldn’t follow much of your argument, but I enthusiastically agree with your conclusion: an inherently unknowable future shaped by the interaction of (1) our own individual and collective decisions and (2) random contingencies impossible to either predict or control. The past is determined and unalterable; the future is unknowable, but the present is all there is, and our past behavior has no necessary effects on our present decisions.