I did exactly that (wife’s family lives in Beijing).
Various parts of Beijing and Nanjing have been under relative “lockdown” at various points in time in the last year. I’m pretty sure this has been reported in Western media too (and I’m sure that other parts of the country have too). I have no idea where this idea that “China has zero COVID lockdowns” came from. I suppose it may depend on your definition of lockdown.
I don't doubt that lockdowns are happening, which is why I listed the presence or absence of them as one of the two obvious things that can be observed by people living there.
I do have doubts that their actual case numbers are too far off from reported case numbers. (Because mass sickness and death, just like lockdowns, would also be obvious to observe.)
Lockdowns, or mass hospitalizations/deaths from Covid are a bit difficult to hide from the people living through it, if either of those two things are happening, everyone would hear about it through the grapevine.