In answer to your questions, it is not so much getting extra quotes from secular writers in the first century who mention Jesus. Rather, the focus should be on the New Testament's reliability as historical documents written by eyewitnesses or close eyewitnesses of Jesus.
One idea I have is to take skeptical arguments one by one and post them as questions here. You can then use this site as a reference for providing a fair platform for reading about and analyzing objections to the Christian faith.
The risk is that some here will tend to vote your skeptical questions down because they don’t like anything posted that challenges their faith. But that goes with the territory.
Also, read up on evidential apologetics by the likes of C.S. Lewis, John W. Montgomery and websites like the Christian Think Tank.
The first order question is whether the New Testament Gospel documents were composed by eyewitnesses or close associates of the eyewitnesses of Jesus. That is a question that relies upon internal and external evidence.
The genre question of whether the Gospel writers wrote fictional accounts is a secondary question. It is also based upon internal and external evidence of the N.T. documents and how they were received as historical genre in the early church. The reading of secular authors, like Lucian & Thucydides on the writing of history can be helpful. For example, Thucydides writes about his method of composing history pretty much like what Luke does with Acts:
Either I was present myself at the events which I described or else I
heard of them from eyewitnesses whose reports I have checked with as
much thoroughness as possible. Not that even so the truth was easy to
discover: different eyewitnesses give different accounts of the same
events, speaking out of partiality for one side or the other or else
from imperfect memories. (History of the Peloponnesian War 1.1).