Can you explain what you mean by 'knowing the source' of the virus? And how that relates to what virologists need to know to predict risk of future pandemics?
We have the complete phylogeny of CV19 (and have had it almost since the pandemic began). China failed to alert the world properly and in time, according to many - but that's not what scientists and virologists study.
The phylogenetic tracking of CV19 is thorough.
Here's an early article (written Feb-March, published March-April). There were already 13 other articles (bibliography at end of that article) on where the virus came from (which can be seen in the phylogenetic research) and many since that time.
We known a lot about coronaviruses
before this pandemic and we know that it is zoonotic (came from non-human animals) and is nearly identical to a virus found in bats. So far, the research shows the earliest known cases were in Wuhan. The way that pandemic risk is assessed is by
studying the R-naught number of each known virus. That's been done many places. These epidemiological analyses do not depend on knowing where the virus came from.
The history of the virus is, of course, of political and historic interest. The ways in which animal viruses jump into human populations are well known and well studied.
It seems to me the only question left unanswered (which has nothing to do with assessing the virus itself) is the human behavior that allowed the zoonotic transmission. Was it wet markets? Or was it human error by a lab worker? The answer to that speaks to human policies and scientific ethics, not to virology or epidemiology. Everyone knows, if they work with viruses in a lab, what the safety protocols are. I figure it would be applied psychology or other human subjects research that would tell us why lab workers make mistakes.
The wet market problem is well known and well documented. In fact, there's way more scientific evidence on the consistent and persistent zoonotic transmission of viruses associated with wet markets, way before CV-19.
But if lab workers were careless and one got the virus him/herself, I suppose you could claim that China knows this and just isn't telling. But that's not an issue that would in any way affect our studies of the epidemiology of CV-19 as a pathogen.
Basics of coronavirus phylogenetic study