I’m sure they would tell you the truth if they did have it and not down play the situation.

There are lot of ways we'd be easily able to tell if covid was actually common in China and being hidden. People are still traveling out of China, and they take antibody tests.

Mask adherence was already a thing in China before this pandemic, so I don't find it hard to believe compliance is very high and China doesn't have major problems with the pandemic.