The Northern Zhou Dynasty was a chaotic dynasty, during which there were many court infighting and political disputes. Most of them are related to a collateral descendant named Yu Wenhu. This man has distinguished himself in military exploits and has a high position. He once ruled for the emperor and even decided the ownership of the throne.
Yu Wenyong is a puppet emperor supported by Yuwen Hu. His situation at that time was the same as that of the later Emperor Kangxi of Manchu Dynasty and the former Emperor Wu of Han Dynasty. But Yuwen Yong is a political genius with great talent and courage. This man lived a simple life, fought bravely, made good use of people and was an outstanding leader. He first designed to kill Yu Wenhu, and then implemented a number of reforms to preserve his strength. Later, the north was almost unified, but unfortunately, it was destroyed by Yang of Sui Dynasty.
As for Wei Chijiong, I have never heard of him.