I don't doubt the general historicity of much of the OT because it's a priestly work, and priests were calendar keepers. The reference material the priests used to compose the OT books were largely priestly astrological records, interspersed with notes about the coronations of kings etc. But to deny it was composed as a narrative to teach a particular view on faith, based on their beliefs at the time they wrote it, denies the reality of how books are written. The Bible is not a collection of dates and events, it's a teaching document, giving you a story, telling you not to sacrifice babies.