There may have been brought even closer relatives of covid-19 to Wuhan by lab personnel. We don't know as for unknown reasons the database of specimens collect

There may have been brought even closer relatives of covid-19 to Wuhan by lab personnel. We don't know as for unknown reasons the database of specimens collected by the Wuhan lab was taken down in September 2019. The distance in years between two viral strains you mention makes no sense at all, as the mutation rate is extremely dependent on environment.