Another possibility is that the prince is indeed dead, which I think is more likely and can leave enough room for the development of modern plot. In the first episode, there is an important but easily overlooked figure, that is, the father of Lion Rock. Why did he choose Park Hao as the prince? Why did you try your best to defend the death of Shiziyan after his death? This is an important clue-because he knows the secret that we and the prince are looking for. Bold speculation-father killed the prince! He once said, "Don't put the prince's wife to shame. Killing the wife of the prince is not only for the family but also for the royal family. " . In the first episode, a poem written by Prince Shizi is the thrust of event development! It is also one of the clues of speculation.
My point of view: 1, Prince Puhe is dead. 2. The prince will definitely return to the era in which he lived, because he has found the answer in modern times, and there are still things to be solved when he goes back. Only in this way can the whole play be coherent, because there used to be a Park Hao who loved his son deeply.
There are still three episodes, and I believe the results will be available soon. I hope to verify it then! This is my guess after seeing it. Hope to adopt!