Films Like Lock Down - What Characterizes the Common Themes

I've thoroughly enjoyed quite a lot of them during lock down. Can you talk a little bit about the themes that they explore in their films? What, if anything, characterizes the common themes that come up? I think the most frequent theme that comes through, often indirectly, is the shock that they experienced as young people during the culture revolution. They found abject poverty. They found exploitation that was not supposed to exist under socialism. And that comes through in a film like yelloworth which is supposedly set in the pre revolutionary era with those kinds of experiences.