The full, detailed, story of the emergence of the SARS-CoV-2 virus will almost certainly never be revealed. China holds and is keeping secret much of the information. The evidence for then lab leak is circumstantial, but solid enough to conclude there was a leak. There is evidence of a two-week shutdown of the pertinent section of WIV and of an unusual traffic surge at Wuhan hospitals. In a culture where bicycles are a main means of transport, that the surge was cars probably means sick people were being transported.
China’s refusal to be transparent is further evidence that it was a leak.