Well I grew up in Beijing and still have friends and friends who live there. So I'm talking from lived experience. People refrain from actually criticizing the government in public in fear of political repercussions but they are not dumb. When government tells you that there is freedom of speech but the word freedom of speech is censored on social media, people recognize that something is not right. Like I said in earlier posts, people put up with all this bullshit because of the economic growth and stability, which is why the government is strengthening its censorship and propaganda ahead of the incoming economic slowdown.
There's also that Chinese people don't like to criticize their country in front of foreigners, because it feels like we lose face collectively.
Well, of course, it's a gigantic country with loads of people. Many are intelligent, educated, aware and immune from propaganda, others are not. Having never even been to China, I can only rely on my friends from there and who live there, but from my experience with them and what they tell me, the brainwashing is very effective with a lot of people, namely older people. Of course, there are also people who are afraid to speak out and perceptions of how much the propaganda works are colored by the people you hang out with.
When talking to Chinese friends and from second hand accounts from my friends who live in China, a very common response to many criticisms toward China is "you just don't understand our millennial culture" (as in culture with thousands of years, not about millennials).
Losing face is certainly something Chinese people worry about, that I have noticed, it's something common in countries where nationalism is strong. An example from another country where nationalism is strong, I remember seeing a documentary with Japanese friends about the terrible labor conditions for truck drivers in Japan and they were so damn embarrassed and flustered, they actually got red in the face and tried really hard to spin it positively. They also don't know a thing, or pretend not to, about WW2.
Like I said before, this isn't exclusive to China or Asian countries (since I mentioned Japan), the USA also has its own brand of brainwashing. My country, Portugal, is also a good example as we are taught (well, at least I was, I don't know what kids are taught today) about about our age of discovery and conquest in a very white washed manner. While I was taught about slavery and invasions, everything was said in a way that was more focused in instilling pride in our country's past than realizing on the barbaric things that were done. This historical revisionism is very easily seen whenever someone brings up that we did some horrible shit and rethink the way we look at the days when Portugal had a big empire. Thankfully, we talk very bluntly and regularly about our dictatorship days, so at least there's that.