One possible answer to this: The Sefer Torah has always existed, but with different “Tsuros” (e.g. Bereishis = Bara Shis (He created in 6 days)). In other words, the letters existed, but the spacings were different hence different words and sentences.
The Torah was supposedly “re-spaced” by Moshe Rabbeinu so that we could derive benefit from it to this day.
Mack Locus (Machlokes)! Hah!
To quote a line from “Cross Currents”:
“There is not a single question addressed by the skeptic in the video that has not been asked by talmidei chachamim of the past, starting with the question of how Yaakov could marry two sisters if he kept the entire Torah. (Ramban’s answer – that he observed Torah law only inside Israel, but not outside – is well known. Fewer know of the Maharal’s approach: the Avos only kept mitzvos aseh/ affirmative obligations, but were not bound by any prohibitions.) Those who tended towards taking Chazal literally were faced with more questions than those given to allegorical interpretation. They met the challenge and answered the questions.”