Something I'm thinking about with under-resourced languages is that you have to either be OK with an extensive replacement of vocabulary with English/other prestige language's vocabulary, or you need influential nationalists/ideologues devoting a lot of time coining new terms from native roots. We've seen vocabulary get supplanted with English (Norman/Latinate vocab), and these days we see it even in languages as high-resource as Japanese and Korean (English vocab), especially in business. I suppose this happened to your mother tongue as well in the past.

> but I've no idea where to even start such an effort.

I think there are two arms to this kind of cultural agenda. One is indeed to document it in the ways it is used by native speakers in the domains of life that its speakers use it in.

The other is more accessible and creative, to reform it by drawing it out of homes and villages and making it a suitable vehicle for conversation in the global intellectual zeitgeist. That means giving standard names to every periodic table element, to Newtonian mechanics, to business concepts, and so on, but also to things like "mobile phone", "ballpoint pen", "gym", "soda". A good starting point can come from translating Wikipedia.

To be frank even a language with as ideological a community of speakers as Hebrew borrows a lot from the English/Latinate vocabulary for modern terms. There may be other examples, but probably the language I know to be most successful in such a project is Standard Written Chinese. It got a headstart with the Japanese forming Sinitic calques as Japan modernized in the Meiji era, but then today the standard practice is to form calques for new terms rather than transliterate, which is quite rare.