For the sake of argument I often will accept Markan Priority when doing apologetics. Even though I'm no longer convinced that Markan Priority is the most likely scenario. The following links to video playlists is by a Mormon who seems to be fairly familiar with the Synoptic Problem/Puzzle. The first video in the playlist arguing for Matthean Priority makes an interesting case for why the evidence suggests GMark (i.e. the Gospel of Mark) was written last among the Synoptics and that it used both GMatt and GLuke as sources. As an Evangelical Christian, I obviously don't endorse the video maker's Mormonism or his case for Mormonism. Nevertheless, his arguments AGAINST Markan Priority, and his case FOR Matthean Priority have some argumentative force.
Deconstructing Markan Priority PLAYLIST
https://www.youtube.com/watch?v=oKSP4G6Nh-I&list=PLGACqQS4ut5hTSML4DYKIl8jeZZOErI9X
Reconstructing Matthean Priority PLAYLIST
https://www.youtube.com/watch?v=L6iBtu9FQCw&list=PLGACqQS4ut5i8CVQcNzf4pBIA8hC-AIpN
Who When & Why - the Writing of the Gospels PLAYLIST
https://www.youtube.com/watch?v=ySIIZWu8A6w&list=PLGACqQS4ut5iFeKqqvQPK_dzMnjF7NBhw
