While China has surveillance, it’s generally different methods and to different ends. Assuming certain documentaries can be trusted in the first place, you’re looking at naming and shaming operations for social rules at street crossings and censoring shit like racism and misogyny from social media, things it can’t even do amazingly since they’d have to surveille 1.4 billion people, about 5 times the population of the USA.
Even under central planning and a huge industrial base, we’re not looking at an easy job. Assume general techniques update every ten years, now you have to retrofit a city you built a decade ago. Even with automation, you’d need a huge base of trustworthy people to monitor multiple fronts, all while keeping your nation profitable enough to sustain all this.
It’s always possible, but I just never personally happened to see any significant proof. Strongest hypothesis in that vein is that they knew and did nothing, but even if they used all their capabilities to prevent/stop it then that means they’re more impotent than most people realize, which is a weakness that can be exploited by revolutionary elements.
That said multiple things can be true at once. They could have tried their best to stop it impotently and also used it as a pretext. The American Empire never lets a good crisis go to waste.