"who were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God." In both English and Greek grammar, "who" (English)/"hos" (Greek) is a relative pronoun; it refers back to something that preceded it and qualifies that item.

Yes, but it refers back to those who had received authority to become children of God. They became children of God, and now, John is telling us, they were born not of man but of God. According to your way of looking at this, they were born, than they received, than they became children. This is absurd. Well more later