The main problem with such evidence is that even in a lab-made virus it simply may not exist. Basically, a good genetic engineer can create a synthetic virus that would be indistinguishable from a natural one. Moreover, often researchers deliberately introduce some synonymous mutations into their designs so that later they can discern their strain from natural ones. But if the creators choose not to reveal these markers, it is impossible to distinguish them from natural mutations.
https://yurideigin.medium.com/lab-made-cov2-genealogy-throug...