You see all the time how players on each team are friendly towards each other. Even guys they arent "friends" with. They want to beat each other, no doubt, but it isnt personal and for many it doesnt extend to the non sports areas of their lives.
of course corbin wanted to beat Utah as bad as any given the rivalry/media dynamics. Because hes as much of a competitor as any (that last game showed that). But Corbin and Devin have also wanted to beat each other at everything their entire lives. It wasnt personal then and it still isnt. His desire for his brother to be the best version of himself far outweighs the sting of him going to Utah. There will be trash talk, their relationship will be 0% affected
as far as the first part of your comment...player that came to mind is Austin Lee. He was nowhere on the depth chart here and i thought he would maybe crack the 2 deep at BU. But the Austin Lee I saw last season would have been a impact player for us and a major part of the rotation. Im not sure he becomes that player to begin with, though, if he doesnt go to BYU. Utah lost a lot of DL and has available playing time and a staff that develops DL as well as anybody. Im sure thats a draw