Argument for a deterministic Universe

Hi everyone. This is my first time posting on this forum. I have what is hopefully an interesting 'thought experiment' in support of my belief that we reside in a completely deterministic Universe (the ultimate law of causality), as follows...

First, I want to establish a baseline... Imagine a Universe which is completely devoid of life, in any form. Isn't it true that in said Universe, that all events that occur are 100% caused by prior events? Even if we don't know 'how' the events are caused, the events are still caused? With no conscious agent present with the potential to affect the outcome of the event (due to the Universe being devoid of life), there surely is no alternative path that events can take, except for the path they are compelled to take by the unrelenting forces of nature?... that nothing else can happen at any time point, apart from what actually does happen at that time point?... that everything that happens, in some sense, "was always going to happen"... i.e. a deterministic Universe

So my logic dictates that if I can dispel the notions of 'free will' and 'randomness' as illusory, I believe that is enough to 'prove' that a deterministic Universe is our reality?,,.
Here goes...

1. Maybe someone has claimed this before, though I've never heard it said, but my belief is that we have free will in 3 dimensions, but not in 4 dimensions. Free will in 3 dimensions is just the conventional understanding or 'feeling' we have with regard to free will. We certainly feel free - I can move around or make decisions in any of the 3 spatial dimensions i.e. I can plan a course of action, execute it and see that my action was carried out. That certainly feels and 'is' free in some sense, but it's only free in 3 dimensions. To incorporate the 4th dimension of time, we need to imagine going back in time to any time point where we made a decision (any decision, big or small) i.e. imagine rolling the Universe back in time (like rewinding a video with every scene playing out backwards) to any point just prior to making the decision, so that you are completely revisiting that moment as it was then, in every single aspect - the position and velocity of every subatomic particle in the Universe is identical to the way it was originally and you are identical to who you were then etc... Surely it's true that the option taken in the choice/decision on revisiting the decision, will be identical to the option taken at the first time of choosing? This is precisely because the 'reasons' for your choosing the option the first time around are identical to your 'reasons' at the second choosing (because everything in the Universe is identical in every aspect - your past, your way of thinking, your mood, your blood chemistry, the firing of your brain synapses - every single possible event prior to the choosing moment is identical). Because the option chosen the second time around will be identical to the original option opted for, you are not free in 4 dimensions. In effect, you are free to do whatever you want at any time point, safe in the knowledge that no matter what you chose the first time around, you would repeat the same option on the revisit, and would repeat the same option, regardless of how many times you revisit that very same decision point. This implies that all of our decisions are not free in 4 dimensions, which is the greater truth when compared with 3-dimensional free will. All our choices are just part of the causal chain of prior events and hence are subject to the laws of causality, like everything else.

2. To dispel 'randomness' as completely causal also, imagine going back in time to a coin toss or to a random event like a decaying atom of Uranium. Again, imagine rolling the Universe back in time just prior to the event in question. Will the outcome be the same upon revisiting the event in question? The important thing here is not to confuse subsequent repetitions of the experiment as proof that randomness exists e.g. in the coin toss event, of course multiple tosses in 3 dimensions (one after the other) will lead to different outcomes, due to slight differences in the factors at every toss being carried out. But that is not what I'm describing when imagining rolling the Universe back in time to the original toss. I am talking about going back to the very same original toss and repeating 'that' toss only. So in effect, the infinite factors that influence the outcome are identical in every aspect e.g. the position of the coin on the index finger initially, the atmospheric conditions (humidity, temperature etc..), the force being applied by the brain down the nerves and muscles in the arm to carry out the toss etc.. All of these are identical. Surely those factors being identical in every aspect implies the outcome will be identical (in 4 dimensions), no matter how many times you return to the same 'original' toss? This completely removes randomness as a feature in a 4-dimensional Universe and hence those events that we call 'random' are subject to the laws of causality, like everything else.

I believe that dispelling those two pillars of confusion (free will and randomness) leads to the inexorable conclusion that all events in the 4-dimensional Universe are caused, regardless of 'how' they are caused. Eminent scientists often seek refuge in quantum mechanics as the savior of free will and randomness, but their pursuit is concerned with 'how' things happen. This is because in their world, the emphasis is on finding the best model for making predictions. My point is that 'how' things happen is irrelevant. If we are confident that every single event that happens (right down to the Planck length) is caused, then the conclusion has to be that we live in a deterministic Universe, where the only events that can happen are the very same ones that do. Nothing else is possible except what actually does happen. It is an inescapable movie being played out and we are all a part of it. Yes, you are free to do anything you want to do at any time point, but safe in the knowledge that no matter what you choose, you were always going to make that choice at that time point... i.e. a deterministic Universe...