There is a claim that a couple of researchers at the WiV got unwell with Covid a few days before anyone else. That would be an argument in favour of a lab leak. But I don't think it's established beyond doubt that this claim is true, and it's not a knockdown argument on its own.

The NSA might have access to Chinese top secret government records saying "oh shit, one of our experiments got out into the wild, cover it up!". Without seeing a smoking gun like this though, I remain on the pro-zoonotic side.