The goal of life being moksha and only one with सात्विक गुणs, that is, a गुणब्राह्मण gets the knowledge and is freed, so the effort needed is for everyone to become a गुणब्राह्मण। There is no dispute in this regard. A person who progresses to become one who has such qualities either gets moksha in this very life or is born in a family where this journey progresses. This is not a point of disagreement either. What this essentially means is that the person who needs to put an effort to develop particular qualities is not born in a family where there are already such qualities present. Therefore, it is also clear that a natural गुणब्राह्मण is born in a ब्राह्मण family, that is, as a जातिब्राह्मण। It is a different matter that if he feeds his रागद्वेषs, he is taken away from the goal into another and therefore might degrade to a गुणशुद्र too, akin to how a person born in a शुद्र family can progress to a गुणब्राह्मण। Else, the function of कर्म and कर्मफल as described in all scriptures, which includes जन्म, would stand contradicted.
This whole thing said above is, unfortunately, amiss among many!
ॐ तत् सत्।