Dating of the Samaritan Pentateuch

Jews and Samaritans: The Origins and History of Their Early Relations by Gary Knoppers, the dating of the SP is around the 2nd to 1st century, and there wasn’t really a “pre-exilic” SP, as the Pentateuch began to emerge in the 5th century. According to Knoppers, “the SP was developed with its distinctive sectarian readings out of one particular family of Pentateuchal texts at a relatively late date, this has significant implications for our understanding of the editing and transmission of the Pentateuch (or proto-Pentateuch) in the late Persian and early Hellenistic periods (p. 188).
So there was never really a single authority on the Pentateuch and so the DSS, MT, LXX, and other Jewish Pentateuchs began to diverge from the SP gradually over time. However, a drastic shift occurred when sectarian additions were added after the destruction of the Samaritans Temple at Gerizim by the Maccabees.