Folk tales which are at the core of Bible texts would have originally been transmitted verbally within families and probably by itinerant storytellers. The majority would have been illiterate and little the worse for that but to them the idea of something written down would have had almost magical implications and if the illiterate were told these markings on vellum or cut into stone were the words of God, by association they would be revered as sacred.
Once “sacred” is applied to anything, people’s expectations rise beyond reason and the if the words were assumed to be from god then the medium of transmission would also have to fittingly be perfect and immutable. Notice how the Genesis here is called “apocryphon” or secret text, creating a sense of mystery and awe.
However as shown here with the Genesis scroll, any manuscript is subject to deletions, alterations and additions. Each cultural centre holding texts might view their own copies as the authentic ones for status reasons but in reality there could be no authentic sacred versions. Nevertheless it would be a religious coup to claim that all other versions but your own were the true words of God and no doubt this trick was played on the peasants. Once successfully accomplished, the influence of the preacher and his synagogue would have been greatly empowered.
The various manuscripts in circulation accumulated additions (you have supplied the evidence FTS) and were edited over time. The idea that there was an original Bible is absurd, even the Jewish writings today (Tanakh) do not constitute what Christianity calls the OT. Even after the collection of books known as the Bible were given the imprimatur in the fourth century by the Roman Church they still kept revising it. The Protestants later deleted about seventeen of these books. Nothing is fixed or sacred, the reality was fluid and subject to prevailing religious orthodoxy.