Can you elaboprate on your list of sources ? What they say, when they lived, how reliable they are ?
For instance, didn't Papias report that Mark's Gospel did not present events in the correct chronological order ? Surely that is directly relevant to any claim of reliability.
Actually there seems to be disagreement over whether Mark wrote whiel Peter was alive or not. The question of the chronological order suggests that the final redaction of the material - at least - was written after Peter was not available to answer such questions.
Of course this means that Mark is second hand. And since one of Matthew and Mark is almost certainly dependent on the other it strongly argues against the Gospel called Matthew being written by the Disciple Matthew.
I looked at your post on the other thread and it seems there is no agreement in your sources. It is claimed that Mark write and published while Peter was alive, that Mark wrote when Peter was around and published after he was gone and that Mark did not write until after Peter was dead. But even the source which claims that Mark published in Peter's lifetime indicates that Mark did not consult with Peter on his writing.