The 1611 KJV does not preserve all God's words down to the number of the noun at Deuteronomy 33:17. At Deuteronomy 33:17, the 1611 KJV changed this noun that was singular in number in the Hebrew Masoretic text and in all the earlier pre-1611 English Bibles to a plural.
Do you contradict you yourself in your attempts or efforts to excuse or rationalize the changing of the number [singular/plural] of original-language nouns in the KJV?
There is a plural form for this Hebrew word, which was not used at this verse (Deut. 33:17). The number of the Hebrew word at this verse is the same as its number at Numbers 23:22 [singular].
In his 1848 Bible (KJV) and Commentary, Adam Clarke wrote: "Reem is in the singular number, and because the horns of a unicorn, a one-horned animal, would have appeared absurd, our [KJV] translators, with an unfaithfulness not common to them, put the word in the plural number" (I, p. 834).
You are trying to turn a doctrinal statement about God’s preservation into a claim that all English translations preserve the Scriptures in the same way. Preservation is defined by Scripture as God keeping His words down to the number of the noun and down to the smallest stroke in the inspired languages. Preservation concerns the text God gave, not every later translation of it. A translation may be accurate or inaccurate. Its accuracy does not determine whether God preserved His words. Preservation is God’s work, not man’s performance.
Your question about the NKJV does not touch the doctrine of preservation.
The issue with modern English versions is their underlying text and their translation choices. That is a question of accuracy, not a denial of preservation. Scripture does not teach that man preserves God’s Word. Scripture teaches that God preserves His Word. The Masoretes transmitted the text they received. God preserved His words. Later editorial opinions do not change that.
Concerning Deuteronomy 33:17, you are again trying to turn a translation choice into a doctrinal claim about preservation. The Hebrew singular can be used collectively. Hebrew frequently uses a singular noun to denote a class or group. Translating a collective singular with an English plural does not deny the number of the noun. It renders the meaning of the noun in English. Paul himself builds doctrine on the number of a noun in Galatians 3:16, and he does so by interpreting the inspired Hebrew usage, not by imposing English morphology on Hebrew idiom.
The warnings against adding to or taking away from Scripture define the moral responsibility of men. They do not redefine preservation as depending on perfect scribal behavior. You said that a scribe who omits a word “did not preserve one of God’s words.” That is a doctrinal claim about preservation. If omission means a word was not preserved, then preservation fails when a scribe errs. That is the logical implication of your own statement, not something I have invented.
Preservation depends on the faithfulness of God. Translation choices do not overturn it. Human fallibility does not overturn it. Later editorial opinions do not overturn it. God preserves His words.