Why and how the text could be Bavarian

[JoJo_Jost]

I'm absolutely sure many people have considered this before. It's been over 100 years of active research. However, this hypothesis runs into many problems, that's probably why it never got traction.

I'd be really happy to find a source here, if anyone has tried this before! Above all, defining the bigrams around the blank spaces as vowel ciphers!

For example, how does this approach explain the labels? Labels are overwhelmingly consist of a single word, labels with spaces are a minority. Are you suggesting there are no vowels in labels?

That’s exactly what I wrote earlier: Labels are consonants without vowels, which is why they’re so surprisingly short.

And, by the way, that was a known form of cipher in the Middle Ages:
One example of this is Robert Bacon’s thirteenth-century "Epistle on the Secret Works of Art and of Nature and on the Nullity of Magic". The Epistle contains seven secret methods of communication, such as words that omit vowels, hybrid languages (in which words might alternate between Latin and Greek, for example),shorthand and artificial languages, invented languages and alphabets, figurative language, geometric characters, and magic spells."
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In addition, medieval scribes omitted vowels for practical reasons as well—for example, in abbreviations, sigla, nomina sacra, etc...

So please, it really isn’t that far-fetched.  (Mainly because they're labels, and that gives you, so to speak, two sources for deciphering them.)