Who wrote the four Gospels? Names offer clues, but not necessarily the answer.
First three are known as the synoptic Gospels because of their similarities

The first four books of the New Testament are known as the Gospels of Matthew, Mark, Luke and John, respectively, but that doesn’t mean that those were the names of the authors. Nor does it mean that their order has any significance.
There’s more that we don’t know …