I’m not sure historians present them as eye witness accounts, or if they present themselves as eye witness accounts. Luke and Acts are very important, and are both written by a non-witness who was compile reports from earlier manuscripts and oral histories, in some ways as current day historians do (though certainly not entirely so).
That is unfortunate. I give some pointers here: Peace Be With You - #3 by swamidass.
We also have to distinguish between the “Bible” as is quoted around and purchasable on amazon today, and manuscripts from the past. If all we had was a current print, we could infer things were added in later. However, with the original manuscripts, this becomes evidence against such claims.
NT Wright catalogues about 8 Messiah movements from 100 years before to after as historical “controls.” Gary Habermas can make his case entirely from non-Biblical documents (e.g. Tacitus and Josephus), and explains this in detail in this lecture. He is not an apologist by the way, but a well respected historian.
You are a brilliant scientist, who has already helped me clarify my thinking on several points of phylogenetics. You however you know very little about historical artifacts of this time period. I think you are mistaking ignorance of the evidence for absence.
If you care to get informed, perhaps read this book, which has been well respected among historians, even non-Christian historians:
Or read a very high level summary of one of the arguments in the long 800 page book here: