I'm saying that it's complete nonsense to say that there's a (1/20)^7 chance of 7 amino acids matching. We're talking about viruses that are descended from a common ancestor, not random, independently distributed coin flips.
> ratg13 seems to be a much more recent ancestor.
RaTG13 is not an ancestor of SARS-CoV-2. The two viruses share a common ancestor.
> Why would ace2 be much better preserved between sars2 and sars than between sars2 and ratg13?
ACE2 is a human protein. Neither SARS-CoV-2 nor SARS-CoV have ACE2. If you're talking about the RBD of the S protein, then note that the RBDs of SARS-CoV-2 and SARS-CoV are only 73% homologous, which is a pretty massive difference.
Stepping back for a second, you're diving down the conspiracy-theory rabbit hole with very little prior knowledge of the subject. That's just going to make you easy prey to a lot of nonsense. Really, instead of reading blogs that claim to have found the secret truth about SARS-CoV-2, listen to what respected virologists have to say about it. Do some basic background reading on virology and coronaviruses. Read some review articles from scientific journals.