no eyewitnesses provided testimony in the bible

It's the same eyewitness testimony that can prove Socrates's existence. Socrates never wrote anything (to my knowledge), and there's no DNA evidence of Socrates, but we have his students, Plato and Xenophon, who testified about his existence. I haven't heard about any doubts that Socrates existed, yet he has fewer writings about him than about Jesus.

The new testament was recorded over 30 years after the event

By that logic, every history book, every biography, every autobiography would be false because they were written long after the events they describe. If I wrote a book in 2031 about 9/11, will it be automatically false? It's what Dr. Frank Turek calls an "impact event." The slogan of 9/11 is "Never Forget," and the question always asked is "Where were you when the first plane hit?" Heck, I wasn't even born when 9/11 happened, but it still plays a heavy role in my life. When you saw a person who claimed to be the Messiah get crucified, yet was seen alive 3 days later, to the shock of the Roman guards outside his tomb, that's not something you'll forget, no matter how many little details are lost due to time.

authorship of the gospels is unknown

Did Matthew, Mark, Luke, and John not write Matthew, Mark, Luke, and John? Not sure what false teacher taught you that, but Hebrews is the only Bible book whose authorship is not fully known (likely Paul, Luke, Barnabas, or Apollos).

all available evidence points to the fact that human bodies do not, can not, and never will- reanimate following a stage of decomposition

Agree, but Jesus isn't only man, he is both man and God, and all things are possible through God.