Yep, the Sons of God, or angels, fallen or not, screwed the daughters of man, and their babies were the Nephilim. The First Book of Enoch names the Sons of God as fallen angels. And yes, you will say that is a non-canonical book, but I am non-religious, so all religious texts are just fairy tales to me and I will use whatever fits the situation/setting.
Note, in Hebrew, sometimes the Hebrew word Elohim is singular, and sometimes elohim is plural. The adjective Eloah means "divine". The plural Elohim sometimes functions as an abstract noun, "Divinity". It normally does so in contexts where it is a proper noun, a name, that takes a singular verb. So, "Divinity is", or "divine ones are".
The Bible occasionally calls humans "Divinity" (Elohim) or "divine ones" (elohim).
For example, when God tells Moses to talk to Aaron, God tells Moses, "You will become Divinity for him." (Exodus 4.16). Similarly, telling Moses to talk to the pharaoh, "See (it), I gave you (to be) Divinity for Pharaoh." (7.1). Moses is a normal human, but he serves as the image of Divinity when speaking on behalf of Divinity.
Remarkably, when a criminal is brought before a judge, the Bible calls this human judge "Divinity" (Elohim). (Exodus 22.8). The human represents the justice of God.
Relatedly, in the context of doing good actions, God says to Israel, "You are descendants of God your Divinity". (Deuteronomy 14.1). One is the image of Divinity when doing compassionate actions. The context also implies some sense of immortality, so as not to scar ones body in memory of the dead.
And so on. In some contexts, humans are Divinity.
In the context of the Nfilim, the Hebrew for "the descendants of divine ones" can be understood in the sense of being the "members" belonging to the group who are "of divine ones". Compare how the phrase, "the descendants of prophets", means the persons who are prophets. Thus, "the descendants of divine ones" are normal humans who are worshiped as divine gods.
Alternatively, perhaps the Bible implies, these "descendants of Divinity" are originally righteous humans who do compassionate actions and speak prophetically, thus become Divinity in this sense. They grow powerful, but unfortunately, start to abuse their power.
Either way, whether humans who are worshiped as gods, or humans who do the will of God, these divine humans are normal humans.
From an archeological perspective, I tend to assume these are humans who are worshiped as gods, namely polytheism. So by analogy, Zeus would originally be a human who would be one of these divinized humans, and Herakles would be one of the Nfilim, a "hero", who descends from him.
However, judging by how the terms, "Elohim" and "descendants of Elohim", are used elsewhere in the Bible, the biblical perspective may well imply that these parents of the Nfilim are originally righteous humans who do the will of Elohim. But. Who have abused their authority.
Psalm 82 is instructive here. And remarkable. Essentially, God "Divinity" stands before the judicial court of "divine ones". God says that despite the fact that they actually are divine, they will die the way normal humans do, because as judges, they fail to protect those humans who powerless.
Psalm 82
אֱלֹהִים נִצָּב בַּעֲדַת אֵל בְּקֶרֶב אֱלֹהִים יִשְׁפֹּט
עַד-מָתַי תִּשְׁפְּטוּ עָוֶל וּפְנֵי רְשָׁעִים תִּשְׂאוּ
שִׁפְטוּ דַל וְיָתוֹם עָנִי וָרָשׁ הַצְדִּיקוּ
פַּלְּטוּ דַל וְאֶבְיוֹן מִיַּד רְשָׁעִים הַצִּילוּ
לֹא יָדְעוּ וְלֹא יָבִינוּ
בַּחֲשֵׁכָה יִתְהַלָּכוּ יִמּוֹטוּ כָּל מוֹסְדֵי אָרֶץ
אֲנִי-אָמַרְתִּי אֱלֹהִים אַתֶּם וּבְנֵי עֶלְיוֹן כֻּלְּכֶם
אָכֵן כְּאָדָם תְּמוּתוּן וּכְאַחַד הַשָּׂרִים תִּפֹּלוּ
קוּמָה אֱלֹהִים שָׁפְטָה הָאָרֶץ
"
Divinity (Elohim) is stationed in the council of Deity (El).
In the midst of divine ones (elohim), the one will judge (them).
Until when would you ones judge (by) evil? You ones would lift up the presence of malicious ones.
You ones must judge (for) a poor one and an orphan. You ones must do altruism (for) a humble one and an impoverished one.
You ones must make the poor one escape. You ones must rescue the wanting from the hand of the malicious ones.
(These divine ones) did not know (it). They will not understand (it).
They will walk around in a darkening. They will make all of the foundations of the land wobble.
I myself said.
You ones are Divinity.
All of you ones are the descendants of the Highest.
However, you ones will die as humanity (does).
And you ones will fall as one of the chiefs (do).
Divinity, you must arise! You must judge the land!
"
This Psalm can easily be understood to be about "the descendants of Divinity" and their Nfilim who are born from them. God gave them power to do good, and to judge fairly. But they abused their power, and damaged their land. In some sense, their unjust violence caused the flood.
The "descendants of Elohim" are normal humans who are in power over other humans. They abused their power, and used their power, to take whatever women they wanted. The "daughters of humanity" are from the human masses who lack power, the non-elites. The "descendants of Divinity" are normal human men who have normal human semen, who produce normal children with normal human females. The descendants, the Nfilim, are normal humans.