You Are Left to Live in Lingnan, and You Actually Become the Crown Prince of the Tang Dynasty?

Travel through the Tang Dynasty and become Li Shimin's sixth son, Li Shu. As the son of the legitimate daughter of Emperor Yang of the previous dynasty, Li Shu did not want to be involved in the struggle for imperial power and asked himself to go to Lingnan to become a free prince. But Lingnan is suffering, so we have to do something good for the people! Build roads, make glass, study farming methods, and fight against bandits and chieftains... Isn't this what the prince should do? How come my father has caught my eye and insists that I return to Beijing and become the crown prince of the Tang Dynasty? Li Shimin: If you don't become the heir to Chang'an, do you think you're going to ruin me? Yuchi Gong: Sixth Prince, what kind of musket of yours can you borrow from me? Li Zhi: Sixth brother, if you continue to stay in Lingnan, the emperor will have trouble sleeping and eating! Wu Meiniang: Your Highness, I heard that you have researched some beauty pills, and I would like to give it a try...