The 'Chinese' Theory: For and Against

[ololololo]

But the Author in the Dictation Scenario too learned the local language from scratch.

He didn’t study it. He learned it to speak, not to study. That’s the difference.

but left some names untranslated.

I’m not arguing that the author might not have known what a particular plant looks like. But the point was that, according to your reasoning, the author didn’t understand the text at all. That is, he was simply recording sounds as they were dictated, without really understanding what he was writing. This is an absurd contradiction. Even in the context of this theory, it’s simply impossible.

Like the Phaistos disk, the Antikithera calculator, the Rodia Towers, the Dead Sea War Scroll, Oetzi's mummy, the Kaaba, Nan Madol...

VMS in your reasoning appears to be the result of some very intricate theory. For example, Nan Madol is a very interesting architectural site because it does not conform to the expected technologies of Oceanic peoples. Nevertheless, it is essentially just structures made of megaliths. That is, it is possible to find a rational explanation for why and how this was done.
The story itself—“a European merchant went to China, learned spoken Chinese, and suddenly wanted to record medical books. He created his own shorthand system to record sounds and decided to use it to record SBS”—sounds more or less plausible, but at best, it’s just possible. However, it can’t simply be applied to VMS, as contradictions will arise, and that’s why the theory continues with something like “but then the author suddenly became impoverished, got hold of some dirty scraps of parchment, found some impoverished orphaned children who wanted to copy his random letters, but oh damn, they made so many mistakes in the text that we can’t read it! And when they were drawing scribbles, instead of the author’s drafts, they took their favorite European manuscripts or re‑drew them!”. It’s possible, but in my opinion, it’s incredible. 

Sometimes it seems to me that you’re just trying to explain absolutely everything using Chinese theory. This inevitably leads to contradictions.