Israel is to be a light to the nations, and to lead them to knowledge of God. Those of the nations are not required to convert to Judaism in order to worship the God of Abraham, Isaac, and Jacob. Some will choose to do so, certainly. Those who do not are to follow the laws of the covenant of Noah. They couldn't retain their pagan practices while purporting to follow the God of Israel.
Then the coming of Jesus changed nothing. Which I guess is your point.
If Jesus just came to call the people to return to the Covenant, then He is hardly much of a figure.
What are we to make of Jesus sending the Apostles out to all of the nations? This is certainly unprecedented. This is something new.
SD