To be honest, the "evidence" I've seen so far boils down to stating that a virology lab was nearby the first outbreak so sure it must have come from that lab and couldn't have come from a wet market or elsewhere. In other words, evidence is confused with plausible storytelling, in incredibly common mistake nowadays.

What's mildly infuriating me about this is that the people who push the lab escape hypothesis seem to have political motivations, but the wet market origin hypothesis is much worse for China. Although they have officially prohibited many of the practices and animal abuse that make it easier for viruses to jump to humans from other hosts, these practices remain widespread. It's much easier to secure virology labs than tens of thousands of semi-legal and illegal wet markets.