I don’t think this is nearly as much of a problem as people think. The Bible still gives direction to the church, but it does it as a historical narrative rather than as a universal blueprint. In simple terms, the church is the historical people of God. It has the purpose that it has always had: 1) to be God’s new creation in the shadow of Babel; 2) to mediate between God and humanity as a priestly-prophetic people.
At a moment of supreme crisis in the first century this people was saved from oblivion and transformed by the death and resurrection of Jesus and the gift of the Spirit.
So we now—in the West—continue to be 1) a new creation, in our clumsy and inadequate way, and 2) a priestly-prophetic people serving the interests of the living creator God in a world that is now rapidly abandoning its Christian heritage. Discipleship is learning how to do this well on these narrative assumptions.