Exum will be fine guys. Yes, he will probably struggle in the upcoming season as he adjusts to playing basketball again, adjusts to his bench role behind Hill, and continues to adapt to the NBA game. Remember, he basically didn't play any high level competitive basketball for a year or so before he got drafted, and before that his only real experience was the FIBA world championships, which is a different game to the NBA as I'm sure most of you are aware of from watching Gobert and others in the Olympics this year. But he's got such a high BBIQ, elite work ethic, and most importantly is very coachable, and Snyder will have Exum starting to somewhat live up to the insane offensive potential he has on the offensive end while reinstating his elite defense after conditioning and adjusting back to the game. He will probably hit a 2nd rookie wall due to missing the prior season, but with George Hill in place Exum will be able to play hard in limited minutes, and be given the opportunity to slowly build his endurance back up so that he's in game shape by hopefully post all star break. The Exum expectations should be tempered until Year 4 for him, assuming he gets through this upcoming season without another major injury. That's the primary reason why the Jazz brought in a guard like Hill in the first place - it's just a nice fit that he was able to fill other needs as well like shooting.
A bloke I work with has a brother who plays in our national basketball league, and I've had the priviledge to speak to him and other players on a few occasions. These guys are vets in their early 30s. Whenver I ask about Exum, they all tell me the exact same thing. He's got all the tools to be a great player, and he's one of the smartest basketball minds they've ever seen out of a 16/17 year old back at the Australian Institute of Sports. He's got elite work ethic, and will do everything he can to become the best player he can be. I can tell you for a fact that if you asked the same guys about Ben Simmons, you wouldn't receive as glowing of a report on him as you would about Exum, despite the fact that Simmons is the far more talented/gifted player. When I asked them about Exum's struggles in his rookie season, without hesitation they all just chalk it up to the fact that, like I mentioned before, he hadn't played high level competitive basketball for essentially a year, and the NBA is a huge step up from Australian high school ball/FIBA U19 ball. They have zero doubts that he will be a good player, and despite a few concerns like his shooting, they all think he could become a great (all star or better) player too. Kid is only 21 years old, and if his rookie year was considered to be like his college year, then his 3rd year in the NBA and his 2nd that he can actually play in should be viewed as a rookie year.
Sorry for the wall of text. I don't post here often, but I do lurk a fair bit during the season and I thought on the topic of Exum I could actually contribute something worthwhile. Jazz are going to be a great team this year, looking forward to your season!