I freely admit that I used the Book of Mark by the reference that is used by every Holy Bible in Christendom and has been for 2,000 years. In my John MacArthur Study Bible, Macarthur states,You said they were written by Matthew and Mark. I stated there is no evidence to that. You stated it as a fact and it very likely they did not write them. Did you google and read some of what the Biblical scholars said? Explain to me how you know for sure, when there are many (much smarter than us and just as Christian as you) who state that they probably did not or it just can not be proved.
"Unlike the epistles, the gospels do not name their authors. The early church fathers, however, unanimously affirm tht Mark wrote this second gospel."
I assume that you are referring to The Synoptic Problem, MacArthur states as the bottom line,
"The simplest solution to the Synoptic Problem is that no such problem exists! Because critics cannot prove literary dependence between the gospel writers, there is no need to explain it. The traditional view that the gospel writers were inspired by God and wrote independently of each other - except that all 3 were moved by the same Holy Spirit (2Pet.1:21)- remains the only plausible view.
Here is my bottom line. For the last two thousand years the books have been named as they are today. The early church fathers concurred with the authors of the gospels. You, nor anyone else, can produce proof to the contrary. The ball is in your court to prove otherwise.