1. Let's be clear what we're talking about: it's the Voynich manuscript, written in an unknown script, for an unknown language, a popular puzzle for linguists/codebreakers.
https://en.wikipedia.org/wiki/Voynich_manuscript2. Proto-Romance cannot by definition be "discovered", because it is the linguistic hypothesis linking the modern Romance languages. Early Italian, or Late Latin, or Pre-Romance, or whatever you want to call it could be discovered, and to some degree this is just a terminological issue, but at the same time there is a good reason to not believe a real "Proto-Romance" ever existed: Latin was already geographically split by that point, such that although the different dialects/languages remained in contact and mutually intelligible to some degree, part of their development was independent drift rather than strictly coming from a single ancestor "Proto-Romance". From a comparative perspective it is useful to discuss that idealized proto-language, but it is idealized.
3. Various explanations for the manuscript have been proposed; none are accepted. Among other things, it may be a natural language:
https://en.wikipedia.org/wiki/Voynich_manuscript#Natural_languageBut as written there on Wikipedia it does not appear to be Indo-European or Romance in particular.
4. The manuscript is not as old as Proto-Romance. Dating Proto-Romance literally is tricky (see above), but let's say it's between 2000-1500 years ago. The manuscript is only about 600 years old. That would mean that it is a copy of a much earlier text, which is not impossible, but certainly should not be a default assumption.
5. Mixing of "Proto-Italic" and "Proto-Romance" scripts (I'm not sure what that means conceptually!) makes very little sense, mostly in terms of a timeline: the Latin alphabet was well established by the relevant time. Perhaps the author intentionally obfuscated the text, but why?
6. Many other proposals have been made, just to take one example:
https://ellisnelson.com/2012/08/02/ms-408-the-voynich-manuscript-mystery/If the current proposal is indeed correct and better than the others, and it is Proto-Romance, then it should be very easy to decipher and translate transparently, without any room for uncertainty. If you really believe this, then you should simply translate the whole manuscript, publish it online, and become famous.
7. Some of the short paragraphs translated in the linked papers
appear to be convincing. However, the "Vulgar Latin" is not clear to me (I've studied Latin and can read Italian, Spanish, French, and other Romance languages), and rather than try to guess about this myself, I'd like to see interlinear morpheme-by-morpheme glosses consistent with current publication standards, or at least word-by-word glossing so I don't have to line it up, and to show that the author is not just guessing about plausible meanings but actually translating the text.
It is absolutely important that there is a systematic interpretation rather than guessing, and I am at this point still skeptical.
8. Quite a few aspects of these papers suggest non-standard research. For example, the term "transliteration" refers to changing the writing system of a text but not translating the meaning, but it appears in one of the papers for what is clearly a translation (meaning interpretation in English).
9. If this is a big deal, then it should be making headlines, rather than being shared in its current form. There are many experts in Romance Linguistics, Latin Linguistics, Historical Linguistics, etc., who could verify this if given the chance. It might take some convincing (because so many similar claims have been made), but if this really is the answer, then there should be no serious difficulty getting it verified.
10. Making sweeping claims without providing sufficient, thorough evidence is usually less effective than making more specific claims. (For example, perhaps some of the glyphs in the script really are from ancient Italy, and that hypothesis might be correct regardless of the other points.) Your claims might be taken more seriously by researchers in the field if presented in that way, from the bottom up, rather than top down with the very controversial conclusion presented as the title. On the other hand, in the case of deciphering a manuscript and translating and unknown script/language, a full systematic translation could be the convincing, as mentioned above.
If you want these claims to be taken seriously, I strongly suggest either starting small and finding ways to demonstrate scientifically (which often means slowly!) some of the smaller points, building up to any conclusion. Or leap ahead yourself and then show the rest of us what we're missing once you've fully deciphered the language and can prove it transparently.