For an in-depth answer to your question about the “sons of God” see chapter 14 and appendix C in my book, Navigating Genesis. I do think the sons of God incident in Genesis 6 was a real, literal event. I also believe that their offspring, the Nephilim were real. In Navigating Genesis I show by appealing to the physics of basketball why the Nephilim in some context had to be supernatural. Scripture is clear that the Nephilim were evil. David and his mighty men wiped out the last of the Nephilim.