This is a long article, maybe prohibitively long, but I wonder if it is more in line with what you have in mind? Or at least, it might be a middle ground between the spectrum of what is being said here. It doesn't discount the Bible, but it delves into many other lenses also.....kind of a pull-back, wide-range view.
https://www.bu.edu/arion/archive/vol...d_get-started/
As an aside, the irony of the phrase "origins of Christian God" is that it is itself an oxymoron. The Christian God has no origins. To speak of the Christian God otherwise means it's not the Christian God.