Is the Confucius Temple an overbuilt building? Why? What kind of cultural concept does it mainly embody in the ancient architecture of China?

No, the Confucius Temple was built on the orders of the emperor, that is, on the orders of the emperor. Then there is the status of Confucius, even the emperor has to pay homage to him personally, so no matter what is built, it can't go beyond the system. All this stems from the fact that Confucianism has exerted more and more far-reaching influence in China since Emperor Wu of the Han Dynasty "ousted a hundred schools of thought and respected Confucianism alone".

In addition, there are some buildings similar to Confucius Temple, which are not magnificent. Such as some temples and Taoist temples. It was built to the highest standards. Even the name of the main temple is called "Palace". Everyone knows that the building name of the palace is exclusive to the royal family, but it is not too much to use Taoist temple. Such as Taiqing Palace, Mingdao Palace and Shangqing Palace.