You have a very backwards reading of the NT. The reason the NT doesn't emphasize "Jews" in connection to receiving the Gospel is that the big shock to everyone was how many Gentiles were coming into a predominantly Jewish organization. Acts 15, for example, makes no sense unless you take into account that each and every member of the Jerusalem council was a Torah-observant Jew.
Let us look at Paul’s life to see how he lived out the New Covenant on a practical day-to-day basis: He went to synagogue on Shabbat (Acts 13:14, 17:1-2, etc.) and when he could find no synagogue building, sought out other Jews to pray (16:13). He took a Nazrite vow on his journey long before he knew of a problem in Jerusalem (18:18). He hurried back to Jerusalem to take part in the Shavuot (Pentecost) pilgrimage feast (20:16). He returned with the intent purpose of not only giving alms to the poor, but also to make phosphoras, sacrificial offerings in the Temple (24:17)–undoubtedly including the ones required to fulfill his Nazrite vow (Num. 6:14-17). He was willing to buy sacrifices in bulk to help four other guys complete their own Nazrite vows in order to demonstrate that he was not “teaching all the Jews who are among the Gentiles to forsake Moses, telling them not to circumcise their children or walk according to the customs” (Acts 21:20-26). He insisted under oath to the Sanhedrin that he was still a Pharisee (23:6) and to Festus that he had done nothing either against the Law of the Jews or the temple (25:8).
Paul’s entire post-conversion life is utterly incompatible with a man who believed that the Torah had been abolished by the coming of Christ or that keeping the Torah’s commands or maintaining Jewish identity were incompatible with life under the Gospel.
Your objection to Messianic Judaism well illustrates why we won't call ourselves Christians, however. You believe that God sent the King of the Jews to the Jewish people, prophesyed through Jewish prophets in the Jewish language and cultural symbols for thousands of years, Who then sent out Jewish emissaries (apostles) to the Jews first and only then to the Gentiles . . . to tell Jews to stop being Jewish.
Gentilizing to Jews is every bit as much a false gospel as Judaizing to Gentiles, as evidenced by Paul's rejection of it in Acts 21 and his whole life before and after that point--and it's a false gospel that Christianity as a whole has bought into and used the secular state to enforce since the Council of Nicea (I've got a nice series called Judenrein Christianity detailing this if you wish to have documentation).
Since Christianity has defined itself not simply as pan-cultural Judaism, but instead as a new religion that actively demands the assimilation of Jews, I want no Jew ever to become a Christian.
I want every Jew to one day know the Redeemer of Israel.
There is a difference between the two.
I pray for the day when Christianity jettisons the last remnants of its 4th Century anti-Semitism and says, "Just as American Christians can remain culturally American, and Japanese Christians can remain culturally Japanese, and Nigerian Christians can remain culturally Nigerian, Jewish disciples of the Jewish Messiah can and must remain Jewish."
Shalom.
Whenever we get too critical about “Jews”, I remind myself about the “King of the Jews”, and His interpretation of Judaism is likely much more accurate than His enemies.