Coronaviruses are a big family of viruses.

The particular viruses they were working with were only distantly related to covid. Related in the same way that house cats are related to tigers.

In addition they were not doing “gain of function research”, unless you want to say that they were also doing “loss of function research”. What they were doing was seeing how point mutation affected infectivity both positively and negatively.

We know what they were working with, and it wasn’t the virus that gave rise to covid. There are much closer matches than in other species.