Researchers around the world published papers explaining how they isolated Covid 19. Other doctors replicated their work. More doctors accepted their work as legitimate. I think its safe to say that they followed correct procedures as established by medical science.
If that is not good enough I do not know what is.
Forget about how genome sequencing work on so-called SARS-CoV-2 virus. If it can't be isolated as pure state. Not only that so-called SARS-CoV-2 never been isolated so it can't do genome sequencing nor to really prove its contagion. And there's no so-called human pathogenic virus has really been isolated. HIV they said that cause AIDS neither been isolated nor proven to exist. H1N1 neither been isolated to prove it even exist. Ebola nether been isolated to provide it exist. Zika neither been isolated, too.Â
No so-called human pathogenic virus ever been proven to have satisfied Koch's Postute or even River's Postulate.
Germ theory or subset virus theory to cause disease which is basis of this Covid-19 is all fraud.