"The word "Nephilim" is in the Bible and it is the duty of Bible students to understand its contents to the best of their ability"
So much here: I will limit.
A. Not all are Bible students. I by profession and by instinct might claim "Bible student" as one descriptor, though it is not my widest or deepest focus as student, and though most of my interaction with the Bible is reading the letter, not analyzing the document. But my sil, who spent at least as much time with the Bible, was hardly a Bible student. Built wrong.
B. Not all linguists research ProtoAlgonquian phonology [that l-problem, hey?]. The Bible student called to focus on Pauline thought may have no interest in decoding Ezekiel. And vice versa. I am built to sort out the AfroAsiatic verb and the Slavic palatalizations, the OT chronologies and possible NT Urtext reconstructions. I am not designed for interpreting "Mediterranean" vocabulary or Japanese / Altaic affinities, nor for Nephilim and Beast. More power to those who are so called, but I cannot porofitably do it or read it.
C. Genesis 3:16 / Genesis 4:7: SOMETHING is going on there - at several levels. My conclusion is: When I have realized it is problematic, I HAVE understood it to the best of my ability. Note:
One day some old men came to see Abba Anthony. In the midst of them was Abba Joseph. Wanting to test them, the old man suggested a text from the Scriptures, and, beginning with the youngest, he asked them what it meant. Each gave his opinion as he was able. But to each one the old man said, "You have not understood it." Last of all he said to Abba Joseph, "How would you explain this saying?" And he replied, "I do not know." Then Abba Anthony said, "Indeed, Abba Joseph has found the way, for he has said: 'I do not know."