A couple of great articles about the Septuagint (LXX) that you need to know about are:
W. Edward Glenny, “The Septuagint and Biblical Theology,” Themelios 41 (2016).
This article is an excellent survey of scholarly views on how the LXX relates to the biblical canon and its uses for biblical theology.
This article addresses the question: How does the LXX relate to the Christian Old Testament, and more specifically, what role does the LXX play in Christian biblical theology? The first part of the article is a brief overview of five different approaches to the role of the LXX in a whole-Bible biblical theology. The five approaches are: (1) LXX Priority and Canon, (2) LXX Priority, Hebrew Canon, (3) Hebrew Priority and Canon, LXX Bridge, (4) Hebrew and Greek Are Sanctified by the Spirit, and finally (5) Hebrew Priority and Canon, LXX Commentary. Building on the different perspectives surveyed in this study, it is suggested that that the importance and function of the LXX in Christian biblical theology is at least fourfold: (1) The LXX can function as the source of Christian biblical theology; (2) The LXX is valuable for biblical theology in its role as a commentary on the biblical text; (3) The LXX is a bridge or link between the Christian OT and NT; and (4) The LXX complements the Hebrew Scriptures.
Mark S. Gignilliat, “God Speaks Hebrew: The Hebrew Text and Septuagint in the Search for the Christian Bible,” Pro Ecclesia 25 (2016): 154-72.
Gignilliat critiques T. Michael Law (When God Spoke Greek), J. Ross Wagner (Reading the Sealed Book), and Brevard Childs (Biblical Theology of the Old and New Testaments) about the status and significance of the Septuagint.