Not exactly. The synoptic gospels were written within 50 years of Jesus‘s death. The gospel of John may be a bit later. The point is that many of the witnesses to the events of Jesus ministry we’re still alive together with a large part of the local population. The gnostic gospels were not written until hundreds of years later. And they were written by a mystical group in Egypt, who were not present during the life of Jesus. That is why they contains certain strange ideas.

As to the historicity of Jesus, his life and ministry, Tacitus, a Roman historian wrote about it extensively and acknowledges the facts as they appear in the synoptic gospels. Your information is not correct. There were also over 3000 other contemporaneous writers who wrote about the events in Israel. Not surprisingly it was major news in the day. There is far more historical evidence supporting the facts of the gospels than you seem to acknowledge.

In saying this, does that mean that we should take all the events in the gospels at face value? No. One should always have a degree of healthy skepticism as you suggested. The Jewish population of the era was uneducated as to the forces behind very ordinary events. Like other peoples from thousands of years ago, they were highly superstitious and attributed many natural events to intervention by the gods or God.

One alleged miracle, the feeding of the 5000 or 4000 (depending on the gospel) may well just reflect the fact that lots of people had food with them and became generous when the initial offering was presented. There does not have to be a miraculous explanation for all the events surrounding Jesus’ life and ministry. But that does not mean there were not things that cannot be explained so easily, the biggie being the resurrection.