I don't really know anything about the Chinese system. It does seem to contain plenty of abuse though.

I have thought about education in a socialist system (I'm imagining something more along the lines of the Soviet Union here). I do think that fundamentally, the sorting function is still there, since various kinds of jobs requiring more or less education exist and need to be filled, and that requires some "meritocratic" justification of who gets do what job, some of which do have higher pay and prestige. But precarity doesn't exist in the same way. Everyone is guaranteed a job, with decent pay. And you can take it easy as well, the boss just doesn't have the same power to ruin your life. I think this would take some of the pressure out of the schools as well. But that's just what I imagine, I really don't know how it was in the USSR, neither personally nor have I read anything about it, so maybe I'm totally off.

But I do think you have a point. The wider societal and economic structure would impact how overall abusive the school system is, even when it is or seems quite similar.