The Eldest Princess Returned to the Capital, and Kyoto Was Turned Upside Down!

I Can't Find That Historical Novel Where the Female Lead Is a Grand Princess

The female lead is a princess royal, and her older brother is the emperor. One of his favored concubines is a transmigrator, and in the end, both he and the transmigrator die. The male lead is the prime minister (I think his surname is Pei?). There are also several other men who like the female lead, including a general, an imperial physician, and court officials... Complete.