Thanks for the article!
I just wanted to say something about 2:75-2:79
The verse right before (2:74) mentions how the Jews hearts hardened after Moses' time. And then 2:75 asks a rhetorical question, "do you think the Jews will believe when they distort the words of Allah after they understood it"? You are exactly correct that this is about the continual defiance of the Jews from after Moses' time (2:74). That means they have been playing this game with their scriptures after Moses' time and they continue to do this.
As an analogy, let's say you are admonishing a political party for their actions and you say "how could they be a party of the people if they write laws that impose serious hardship", this is talking about their previous actions and their continuance in this behavior etc.
Quran 2:75-2:79 hints and alludes to the Jewish tendency to tamper with the word of Allah especially when considering the overall theme surrounding the context of these verses of the Jews' general defiance against Allah. These verses do not mention if those corruptions made it into the bible, however in conjunction with 4:157 and other verses that contradict the Torah/Bible, we learn that the Jewish tendency and attempts to corrupt the word of Allah ultimately made it into the text of their scriptures!
This is an unequivocal proof that the Quran teaches they have corrupted their scriptures.