Regarding Imperial Chinese Dynasties: Who had the strongest and weakest control over their citizens?

Hello all! First time heading over to this subreddit because although I usually do my own research for history, I can’t wrap my head around the Dynasties of China no matter how hard I try. I’m particularly looking at the late imperial Chinese period around the 12th century, where I’ve been doing most of my research for other places. Next paragraph is for my questions so I’ll place a little background here. I’ve been building out a DND setting based in the medieval period of the world, but using only 1 continent. To do this, I’ve combined some European medieval countries with Asian countries of the same era, like Feudal England with Shinto beliefs of Japan both 12th century. Another is the Mongolian Empire with Iceland Commonwealth, 12th century just before Iceland got taken over by Norway entirely. This nation is going to be based on Imperial China and maybe late Byzantine (though I do want to make this place very godless so…). The vision is a place unbound by heresy or divinity, and so equipped with arcane knowledge from past ages. However this causes multiple different factions to arise over time each believing they should control the entire region. Power kept in check by egos and squabbling. Irregardless, time for my questions.

Questions Here : How did anyone trust the government when so many Dynasties rose and fell so often? Were the 4 Dynasties of Late Imperial China at war with each other or allies? With this knowledge, what Dynasties had the strongest and weakest control over their citizens?