The supposed early Jewishness of the Church is a Jewish fantasy and I've argued with Jewish Christians about this nonsense. There was Judaizing or adding works to grace, and there was the teaching of grace alone. Christ tore down the wall of partition between Jew and Gentile, "there is now no more Jew nor Gentile..." and "they were first called Christians at Antioch." Christians, followers of Christ, not Gentiles, though some confused Jewish believers make that false claim.
They want a church that feels Jewish to them. So they've started many "messianic Jewish" congregations where some of the trappings of Judaism are maintained such as the torah scroll, the prayer shawl, the shofar, observance of the Jewish High Holy Days, sometimes Saturday or Sabbath worship, even the skull cap although Paul specifically wrote that men are not to have their heads covered in the assembly. There is nothing terribly wrong with any of this but it is also unnecessary and just appeals to their fleshly cultural Jewishness.
The idea that the Church ever became Gentile is just their own cultural obsession probably because of their pre-Christian life. As for Gentile culture, the Church shaped that far more than the other way around.
Edited by Faith, : No reason given.