China put sanctions on Australia that will and have cost their economy billions for implying that the lab leak hypothesis is plausible. Reasonable or not the Chinese government believes suppressing this theory to be a major policy goal. So I expect they’ve either spent orders of magnitude more effort than we ever spent on looking for Ebola’s origins, or they have some reason to believe they wouldn’t find anything.
This isn’t a smoking gun, but it is a dog that didn’t bark.