I appreciate your sincere desire for discovering authorial intent which is why I don't put you on my ignore list as I do others who think that angels mated with women. I realize that some may think that is what it says and are not being belligerent in their eisegesis. I can tell the difference between those who want to know what the text really means and those who are off on a tangent of their own. I respect your opinion on this topic more than most others who don't seem to be willing to reexamine their position.
Let us examine the following text once again from Gen 4:
17And Cain knew his wife; and she conceived, and bare Enoch: and he builded a city, and called the name of the city, after the name of his son, Enoch.
18And unto Enoch was born Irad: and Irad begat Mehujael: and Mehujael begat Methusael: and Methusael begat Lamech.
19And Lamech took unto him two wives: the name of the one
was Adah, and the name of the other Zillah.
20And Adah bare Jabal: he was the father of such as dwell in tents, and
of such as have cattle.
21And his brother's name
was Jubal: he was the father of all such as handle the harp and organ.
22And Zillah, she also bare Tubalcain, an instructer of every artificer in brass and iron: and the
sister of Tubalcain was Naamah
You can question the descent of Adah and Zillah (though I don't think it is necessary) but you can't dispute the relation of Naamah a direct descent from Cain and a daughter of Lamech. Her name also meant pleasant and beauty. It depends on the Hebrew references you consult they all seem to have something similar to Fair, Pleasant, Beauty.
I propose that at this stage in the book of Genesis names had significant meanings and were expected to be paid attention to as part of the narrative. We miss it in English but a Hebrew reader would not. The fact that daughter were mentioned at all when none were in Seth's genealogy is significant. Or since I am in New York at this present time I might say "it was not for nothing" that they were mentioned. We are expected to notice that their names suggested something. Naamah especially seems to have no reason to be mentioned other than to point out her looks. A Hebrew reader would notice but English readers don't. This is why they are baffled by Gen 6:2 when they shouldn't be.
The Hebrew reader of Gen 6:2 immediately remembers these daughters of men that had been previously highlighted concerning their Fairness in Gen 4:22 I think it is VERY STRONG evidence that cannot be dismissed out of hand. One must ask "If not to point out the meaning of her name, why is Naamah mentioned at all?" Let us just say it is much stronger evidence to interpret Gen 6:2 than anything from Job could be.