I know there's been a lot of focus on who starts at the 4 and 5... Reality is the 1-3 have been the same for the entire season and for the entire season UNC has gotten off to slow starts. I tend to think those 3 (Cadeau, RJ, and Seth) simply aren't the best combination on the floor. Cadeau and RJ are very ball dominant guards and while Seth can score without offense being designed for him, he's certainly at his best with the ball in his hands attacking the paint.
So some water and oil mixing in the backcourt perhaps? You combine that with Cadeau and Seth aren't willing shooters (Cadeau is 1/15 from 3 over the last 4, Seth is 3/12 from 3 over his last 5) and RJ hasn't shot the ball well this season.
But not a whole lot you can do with the backcourt. You can't not start Cadeau because he's the only PG on the team. You're not going to bench RJ for Jackson. And Seth is is a 2-way wing on a team that doesn't defend particularly well. If everything were truly up in the air, I would explore Jackson starting at the 2 to get some more size there. Also, Ian's a late shot clock option like RJ is. But that's probably not a realistic option for this team.
Long winded way of saying this is an entire team issue. The bigs and the coach will get the most criticism. They're the easiest targets.
But if Cadeau is generational, he needs to be a tone setter on both ends of the floor. If RJ is an All American, he needs to simply play like one. And if Seth isn't immune from completely disappearing for large stretches of the game too.
This backcourt can be one of the best in the country. But to have that reputation, you need to perform on the floor.