Ontological and epistemological doubt, quantum, and probability

Hello Mikhi, in the liberal sciences you say that there is epistemological doubt that we do not know what reality is. And in a vague reality it is ontological doubt because reality is unclear and not that we lack knowledge about reality. If we have epistemological doubt we can use probability and then we can know what the percentage is that something was like a cube. But if reality is vague then we cannot say what the probability is because there is no probability, like the law of large numbers or in chaos, but it is truly random. But in quantum it is "ontological doubt" and we do use probability. How exactly is this possible? And doesn't that indicate that it is epistemological doubt and not ontological?