From the next link below:
The Masoretic text was produced by Jewish scholars beginning in about the fifth century AD, and continuing until almost AD 1000. They are thought to have worked from manuscripts that were copied in about the second century AD. Thus, this is the newest version in terms of source material.
The Apologetics Press provides what appears to be an objective analysis of the Masoretic Text and Septuagint against the Dead Sea (Qumran) Scrolls:
First, the Dead Sea (Qumran) Scrolls, and thereby the Masoretic text, have a more ancient basis than you imply:
... the archaeological and linguistic data provide scholars with reasonable confidence that the scrolls date from 250 B.C. to A.D. 70.
Secondly it appears you challenge the integrity of the Masoretic Text, but the evidence suggests otherwise:
The Isaiah scrolls found at Qumran closed that gap to within 500 years of the original manuscript. Interestingly, when scholars compared the MT of Isaiah to the Isaiah scroll of Qumran, the correspondence was astounding. The texts from Qumran proved to be word-for-word identical to our standard Hebrew Bible in more than 95 percent of the text. The 5 percent of variation consisted primarily of obvious slips of the pen and spelling alterations (Archer, 1974, p. 25). Further, there were no major doctrinal differences between the accepted and Qumran texts (see Table 1 below). This forcibly demonstrated the accuracy with which scribes copied sacred texts, and bolstered our confidence in the Bible’s textual integrity (see Yamauchi, 1972, p. 130). The Dead Sea Scrolls have increased our confidence that faithful scribal transcription substantially has preserved the original content of Isaiah.
As in the case of Isaiah, before Qumran there were no extant manuscripts of Daniel that dated earlier than the late tenth century A.D. Accordingly, scholars cast suspicion on the integrity of Daniel’s text. Also, as with Isaiah, this skepticism about the credibility of Daniel’s contents prompted scholars to take great freedom in adjusting the Hebrew text. One reason for this suspicion is the seemingly arbitrary appearance of Aramaic sections within the book. Some scholars had assumed from this linguistic shift that Daniel was written initially in Aramaic, and then some portions were translated into Hebrew. Further, a comparison of the Septuagint translation (Greek translation of the Hebrew Bible) with the MT revealed tremendous disparity in length and content between the two texts. Due to these and other considerations, critical scholars assigned little value to the MT rendition of Daniel.
Once again, however, the findings at Qumran have confirmed the integrity of Daniel’s text. Gerhard Hasel listed several strands of evidence from the Daniel fragments found at Qumran that support the integrity of the MT (see 1992, 5:50). First, for the most part, the Dead Sea Scroll manuscripts of Daniel are very consistent in content among themselves, containing very few variants. Second, the Qumran fragments conform very closely to the MT overall, with only a few rare variants in the former that side with the Septuagint version. Third, the transitions from Hebrew to Aramaic are preserved in the Qumran fragments. Based on such overwhelming data, it is evident that the MT is a well-preserved rendition of Daniel. In short, Qumran assures us that we can be reasonably confident that the Daniel text on which our English translations are based is one of integrity.
With Best Regards,