Question

I’m interested in beginning to study the laws of niddah specifically, though I assume the question is relevant to any halakhic field. (The study is not for immediate practical purposes.)
Is there, in your opinion, value in beginning the study from the biblical verses, trying to understand what is written in them and what is not written in them, before moving on to the midrashim of Jewish law, the Mishnahs, and the Talmudic passages?
Formally, the authority is that of the Sages, but I think it is still worthwhile to understand what the Sages said based on a direct or indirect reading of the verses, and what seems to exist independently (perhaps in the Oral Tradition). In our specific case, for example, it seems that in the Torah there is no law at all of "observing one day corresponding to one day."
Is there significance to understanding what the Sages derive from the verses and what they do not, perhaps in terms of weight and obligation (not necessarily practically—in that respect we are bound by them—but, for example, in terms of values: if something clearly emerges from the Torah then it presumably expresses a value that the Holy One, blessed be He, desires, as opposed to things that came from the Sages, perhaps less so).