I'm so pleased that you are considering looking into the Stone Edition Tanakh. You can always order it online at Artscroll.com and many other places online.
I would argue that Paul was a hellenized Jew. He was born outside of Judea, aka Saul of Tarsus.
The Tanakh is simply the Hebrew manuscripts of the canon of the Torah, Prophets, and Writings. The Masoretic manuscript is one example of a Tanakh manuscript copied and edited during the 7th to 10th centuries CE.
As I said in my previous post, the theory is that with the exception of the Torah (the first five books) the Septuagint was NOT translated "hundreds of years prior to christian influence" but was indeed translated by Christians, directly influenced by their theology, in some cases mistranslated for reasons of theology.
Israel always went back and forth, having good kings and bad kings, times of obedience and times of unfaithfulness, you will get no argument from me. However, the prophets were very clear that while unfaithfulness would bring discipline, God would restore Israel, things would be better than ever, the wolf would lie down with the lamb, etc. There has never , ever been a time where God has rejected Israel. Ever.
I know you are sincere in your beliefs, but you have to understand that to me, it is just so ridiculous to read in the Tanakh that God has made an everlasting covenant with Israel, and then to turn around and say that God has abrogated that covenant. You just can't have it both ways without God being some kind of liar. I think both you and I agree that God is not a liar.