Well said.the word nephilim comes from the word, 'fall'. Literally, nephilim, are 'fallen ones'. What does that mean? There are a number of different interpretations.
The expression, 'son of' in the bible can be literal or it can be used metaphorically. Metaphorically it means, that you take on the characteristics of the thing of the person is said to be a son. For example, In Mark 3:17, James and John are called 'sons of thunder'. They aren't literally born from thunder, Jesus is saying they are like thunder - perhaps loud.
Does God have sons? He has Jesus. Jesus is the only one of a kind, son of God.
We are 'sons of God' when we follow Jesus, but not in the same sense. It is an adoptive sense. But it also means we should take on some of the characteristics of God.
In Gen 6, 'sons of God' are contrasted with 'daughters of man'. It is a bit strange to think that 'sons of God' are literally sons, being Jesus is really the only 'divine' son of God.
Are they angels? Perhaps, but it they are 'evil' angels, then they can't really be called 'sons of God', can they? Does God have 'evil children'?
To say that people are 'sons of God' might mean that they are godly people. This is contrasted with daughters of men ('fallen men'?). This is one interpretation.
Kings are also called 'sons of God' (Ps 2). This might be contrasted with ordinary men. This is another interpretation.
The real full interpretation of this passage is now lost. People can speculate. But how helpful is it? Does it bring anyone closer to Jesus? Isn't this the sort of thing Paul warned Timothy against (1 Tim 1:4)?
Thank you.