Where are the tens of thousands of historical doent (sic) relating to [a historical Jesus]?

Sacred Tradition; the ping on of knowledge from one man to the next (actually one community to the next). That's where "Creeds" come into play like the Grotos of Africa ping on lineages dozens of generations back without error. That alone is enough "proof" to p in American Courts of Law. Not to mention the people who started these creeds # in the hundreds (bishops) who represented hundreds of others, then those Bishops and Apostles died holding their creeds more valuable to their lives. There is a Jewish book that records the birth of every Jew nearly (which includes Jesus, Mary, and Joesph). Jews were the #1 record keepers of ancient history, because who you where born under determined how much property you were allowed to own. That fact also backs the historical Accuracy of the Old Testament. Then we have several writings from Saints outside the Bible who died by the romans and insane miracles happened around them. My favorite even was how St. John the Apostle and Bishop was sent to Rome to be executed by boiling oil; he was thrown in and nothing happened so the Romans exiled him on a island in the Mediteranean where he wrote the Apocalypse of John or "Revelation" of John.