True, by definition, and accepted on faith. No problem. But the logic by which we arrive at an uncaused cause is a bit troublesome -- at least to me. The reason we reach so far back into the chain of causation is because we observe that everything has a cause. Were it not for that observation, we wouldn't be searching for the earliest causes and expecting to find them. But when we arrive at the First Cause, we change the rules! Having gone as far back as we can go, we don't say that we're simply stuck for an answer (which we logically are). No, instead of saying that we don't know how to keep going, we just drop the very reason that impelled us to go on this chase in the first place, and we declare that although we got to this point only because everything has a cause, suddenly a cause isn't necessary. This is inconsistent reasoning, which is why the issue of a First Cause is a matter of faith, not logic. Or so it seems to me.
It's not entirely lucid as to why Aristotle rejected an infinite regress of causes, although I suspect that his focus on finding the underlying phenomena of things made him reject motion as the essential nature of existence.
The mere concept of an unmoved mover is of course no evidence that such actually exists. And so perhaps you want to say that since all we see causality, it is more logical to keep it to that much. But the concept of an unmoved mover is not illogical. Nor is it a matter of faith, unless the unmoved mover has a will you can trust.
Of course! the only two options are an infinite regression of causes, or an infinite "causer". Either way, you are faced with a choice that rationalism cannot circumscribe (with apologies to Bertrand Russel, who, when pressed on this point, claimed to be able to conceptualize an infinite series of doors, one behind the other).
A possible exception to this was that hit of acid I did once where I perfectly conceptualized the infinite, but I don't think that will work in this context.
In sum, one can reason about cosmology and determine that there was a beginning from void (or null) - and therefore what the first cause existence must be, e.g. transcedent (non-autonomous).
Simply not true. We observe the opposite at the quantum level. We are surrounded by uncaused phenomena. We are made of them. This is one of those cases, like the rising and setting of the sun, where thousands of years of common sense assumptions seem to be based on error.