Tang Xuanzong's experience and lessons are extremely profound. Can you tell me what courses I should take?

First of all, at the beginning of his succession, he made great efforts to create a prosperous new century, which was comparable to the rule of Zhenguan. Secondly, at the beginning of his prosperity, he was content with pleasure and did not think about making progress, thinking that Jiangshan could sit back and relax the governance of the country and the constraints on officials to appease Li's people. Later, the love for Yang Guifei and the corruption of officials also consumed a lot of national strength, which led to the gradual decline of the Tang Dynasty. Of course, the demise of the Tang Dynasty cannot be said to be Yang Guifei's fault, which is unfair.