I definitely get where you’re coming from. I believe one of the reasons linguists say Standard English doesn’t actually exist is because what’s considered “Standard English” may not be the same amongst all the Englishes in the world. So not only does it evolve and is ever-changing, but it’s different, depending on the country. For example, in American English, we don’t use “whilst.” Also, from what I understand, the Oxford Comma is mostly an American thing and isn’t common in Great Britain (I could be wrong about this).