When did the feudal and patriarchal systems begin to break down and what system eventually replaced them?

Shang Yang's change of law abolished the feudal system and the county system formally disintegrated in Qin Shi Huang and was eventually replaced by the county system The patriarchal system did not strictly speaking end in the Western Zhou Dynasty, because the Western Zhou Dynasty practiced the system of feudalism, but the system of succession of the first-born son was inevitable in the later years of the Chinese system, so the patriarchal system has actually always had an impact