TTWSF, The Bible is an old collection of texts. First collated in the fourth century CE and therefore it might be said to be “historical” in its appearance in time. This does not make it historical in the sense that it is a ”history”, far from it! It is a collection of texts much doctored and edited to suit the propaganda of the users of the books even before their inclusion into the Bible by the Catholic Church. The source documents and stories for the Bible are mainly pagan and do not qualify to make a historian’s account of what is a proper historical record. This is because they are derivative and are not first-hand records by reliable witnesses. Much of the OT Bible content is ancient folk myth dressed up in Jewish costume to make it appear historical.
There is no uncontested evidence that Jesus existed as a historical figure. The most compelling is the mention of Jesus by Josephus which a long time ago was discredited as a later Christian forgery. There is evidence that Adam is a myth. Firstly that the story in Genesis reads precisely as a creation myth would read. Secondly that archaeology has indeed a record of the evolution of Homo sapiens embedded in the datable geological column. I have hands on experience of this and might add that genetics only confirms our close kinship with the earlier hominins such as Neanderthals. As Cofty says most of us (outside of Africa) have a small component of Neanderthal genes. New light is genuinely possible in science when a new species and new evidence is discovered and time will no doubt refine the understanding of the human pedigree.
Adam however remains in the myth category. How on earth could Jesus buy back the "perfect life" which Adam lost? Christianity is pointless if perfect Adam did not exist and yet evidential science precludes the possibility of Homo sapiens being descendents of one such man. If you then say that there was such a man because the Bible says so, what about all the unredeemable men and women who we know lived before “Adam’s time”? At what moment in humanity’s evolutionary chain of life does the ransom sacrifice begin to work?
If no first Adam then certainly no second. The first perfect paradise was a myth and so is the foretold one.