You have some differences in perception of China, which do not correspond to the real situation.
In recent years, China's self-media has been very developed, and no one can hide important things. This is the general trend of Chinese society, and no one can change it, but only adapt, including CCP.
Every time a fighter or missile carries out a related activity, the sky creates some changes. When people find out, they immediately use their mobile phones to record it and send it to Douyin. These videos are quickly spotted and quickly proliferated, and people talk about them extensively. However, usually our discussion will not involve specific names and models, and we will use some aliases instead until an official announcement appears.
If you want to be the first to know these things, you need to know Chinese culture and code language very well.These are unique languages that cannot be translated into English.
The Chinese government does control all public media platforms. But for these messages, there is usually no interference, even if it is the latest state-of-the-art technology. If it can be photographed by ordinary people, it means that it can be made public.
What must not be made public, China has a special place to deal with this kind of affairs. For example, after so many years, there is still no real picture of H20, and many people even doubt that it exists. So, do not doubt the PLA's ability to keep secrets.