I am not unaware of the rabbinic teachings of pre-existence of the Torah and it being God's first and most perfect revelation, etc. And as you have plenty of experience with Christianity I am sure you yourself are not unaware that that kind of language screams "In Principio Erat Verbum" to a Christian. Torah to us is not an it. Torah is a He, and He is its complete expression--like you said, at a higher level than you or I can comprehend.
To your assertion of "Absolutely not" at the idea that a new law would be promulgated:
Whereas the Babylonian schools took it for granted that the Mosaic law, and particularly the sacrificial and priestly laws, will be fully observed in the Messianic time (Yoma 5b et al.), the view that a new Law of God will be proclaimed by the Messiah is occasionally expressed (Eccl. R. ii. 1; Lev. R. xiii., according to Jer. xxxi. 32)—"the thirty commandments" which comprise the Law of humanity (Gen. R. xcviii.). "Ye will receive a new Law from the Elect One of the righteous" (Targ. to Isa. xii. 3). The Holy One will expound the new Law to be given by the Messiah (Yalḳ. ii. 296, to Isa. xxvi.); according to Pes. xii. 107a, He will only infuse new ideas ("ḥiddush debarim"); or the Messiah will take upon himself the kingdom of the Law and make many zealous followers thereof (Targ. to Isa. ix. 5 et seq., and Iiii. 11-12). "There will be a new covenant which shall not be broken" (Sifra, Beḥuḳḳotai, ii., after Jer. xxxi. 32). The dietary and purity laws will no longer be in force (Lev. R. xxii.; Midr. Teh. cxlvii., ed. Buber, note; R. Joseph said: "All ceremonial laws will be abrogated in the future" [Nid. 61b]; this, however, refers to the time of the Resurrection).I haven't made a formal study, but I would wager that every single example you could cite of Pauline/Christian "antinomianism" had nothing whatever to do with the eternal Law binding on all men which was in force from Adam until now, but only the ceremonial and dietary and purity laws and sacrifices that came from Sinai--which, I repeat, were believed at least by some as temporary until the days of King Messiah.
This is my point. Catholics (and other ancient liturgical chr*stians) limit their "antinomianism" to the Laws of G-d given on Mt. Sinai and then express surprise when Luther and his followers take that logic to its natural conclusion. If Biblical law is abrogated, what need is there of post-Biblical law???
Of course the Torah is the logos. That is my point. It is the genetic code of the created universe and preceded it as the blueprint precedes the building. As to what Mashiach will do when he comes (and it must be remembered that Torah Halakhah sits in judgment on all messianic claims), he has not come yet or the Beit HaMiqdash would be standing, all Israel would be engathered in The Land, and the nations would all be worshiping HaShem and at peace with one another. This of course depends on a literal interpretation of the messianic prophecies, whereas chr*stianity has always interpreted these prophecies non-literally ("spiritually")--the engathering of Israel referring "mystically" to the conversion of the nations to the chr*stian church.