The Septuagint vs The Tanakh

Here I look at the definitions of the Septuagint and the Tanakh
The Septuagint is the alleged Greek translation of the Hebrew Scriptures as supported by the Roman Catholic Church including the Apocrypha
The Tanakh as taken from the first two letters of the Torah, Nevi'im and Ketuvim in the Hebrew Old Testament (the Law, the Prophets and the Writings or Psalms (Tehilim)).
Are they different and, if so, which one is correct?
Are there any issues with the Septuagint and how do the Vaticanus and Sinaiticus manuscripts also impact on the New Testament?
By Unknown author - reproduced with permission: http://www.eliyah.com/lxx.html, Public Domain, https://commons.wikimedia.org/w/index...
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