If I recall correctly, China's fault refers to how they failed to contain the epidemic due to their initial approach to the problem, which consisted of censoring and gaslighting reports from doctors in the field and intentionally failing to act on it before it spread.
Also, it didn't helped the fact that the CCP's propaganda machine started pushing propaganda pinning the blame of the COVID-19 outbreak on Italy and Spain when their failure to contain the Wuhan epidemic turned to a pandemic.
Then there is the additional question of whether the virus was the result of gain of function research.
A decent summary, albeit a lengthy read (published this summer, but so far still correct AFAIK): https://www.vanityfair.com/news/2021/06/the-lab-leak-theory-...
(Personally, I’m not so sure the grant is so damning. Perhaps this research is banned in the US, but as one of the papers published said it “could help prevent a future pandemic”, and either way it has nothing to do with potential BSL-4 non-compliance that could have caused a leak. What is unfortunate is the apparent obstruction of the study of the origins of COVID outbreak.)