well, the synoptic gospels were written before 70 AD.
John’s was written between 80 to 90 AD.
The direct primary source of Jesus’ death? We have the beliefs of multiple disciples, the mockery of non-Christians - whether Tacitus or Josephusa etc
The authors of the gospels of Matthew and John were eyewitnesses to Jesus’ life. the author of Mark was taking notes from an eyewitness (Peter) to Jesus’ life
Peter did not write it down. If he did, then that's the direct primary source. We don't have anything like that. So all we can rely on is our faith.