Of course there are many secular scholars who argue in favor of the unreliability of the New Testament texts, however, if we approach the question from a Christian religious perspective, this idea is unacceptable.
The fact is that, especially in recent centuries, thousands of ancient New Testament manuscripts have been found, and not a single one contains any indication that "Jehovah" ever appeared in the texts. There is also no secondary source, not a single early author who hints at a possible theological problem related to this. At the same time, textual researchers of the New Testament (such as Bruce Metzger and the Alands) emphasize that the text of the New Testament can be supported better than any other ancient text, since there are thousands of manuscripts available that are relatively close in time to the original authorship, and although there are various textual variants, these are mostly smaller spelling differences, or theologically insignificant differences. And the Watchtower Society cites these researchers in unison.
For such a decision to remove the name YHWH from all NT manuscripts would have required at least a central church decision, and of course, if the early Christian consensus had attributed this to be a substantial matter of faith, there would have been protests against this tendencies, etc. But there is no such thing, and especially in the light of the fact that the Watchtower Society - adopting the classical Protestant position - claims that there was no indisputable central church authority (like the in the first centuries. (Then, of course, when their "Governing Body" has to be verified, they are arguing te opposite, even though the so-called Apostolic Council mentioned in the Acts 15 was not a permanent body, but an ad hoc apostolic assembly, a council/synod in modern terms ).
"They could argue that in general the NT text was preserved while the divine name in particular was removed, perhaps partly under the influence of Satan."
This position fails precisely because the Holy Scriptures expressly state at many points that God takes care of the intact preservation of His Word, and if the central question of religion is the identity of God, then according to this, God did not take care of the preservation of a content of such fundamental importance.
Because the inclusion of the name "Jehovah" in the NT is not an issue like the verses that were included in the Textus Receptus, but rejected by the newer textual criticism (they are theologically indifferent, or the teachings of the Christian denominations can be supported even in the absence of them), but according to the WTS theology without it, the identity of God based on the existing New Testament text is wrong, or at least confusing, and misleading. Furthermore, according to them, God's people should be named after "Jehovah", so without this, the identity of the Christian congreation itself cannot be supported.
So if God did not actually ensure that His Word would remain intact and authentic, then what is the Bible worth as a religious book? How do we know what else was falsified in it then? This is indeed a slippery slope that WTS theology cannot deal with. According to this, God himself allowed Christianity to fall into astray for nearly two millennia, and in fact, He did not take care of the satisfactory settlement of this issue even today.
"But that Jehovah has played a hand in restoring the divine name in the last days by preserving crucial LXX fragments with his name"
Oh, and then why didn't God preserve the same New Testament text copies, if the issue here was not YHWH's inclusion in the Old Testament, but in the New Testament? Furthermore, such Septuagint copies do not indicate that they were in use either by the main branch of the pre-Christian Judaism or by the original "pre-Great-Apostasy" mainstream of the early Christian church, or that this was theologically that relevant as for the present-day JWs.
Let's not forget that according to WTS theology, the Last Judgment has been "very close" (even on a human scale) since 1914, of course more than a hundred years have passed since then, wouldn't it be about time to finally find such a New Testament manuscript?
I note that according to Hebrews 1:2, the "end times", or "last days" simply means the era of the New Testament revelation, the New Testament age, not the years or decades immediately preceding the second coming.
In addition, the apostle Paul wrote in Romans 3:2 that God "entrusted his words" to the Jews (Protestants also derive from this verse that the Jewish canon is authoritative the matter of the Old Testament canon). Question: based on this, to whom did he entrust his New Testament words?