I would say that without 42 season ending injuries Exum would probably still be in the league today and would be on his way to a 10+ year NBA career. Not what you want from the 5th pick and not what you want from the guy with supposed sky high potential, but it's really not out of the ordinary. Top 5 picks bust and disappoint all the time regardless of where they played before the NBA.
Having said that, no two scenarios are the same. Exum was playing HS basketball in Australia whereas Bilal has at least been playing in professional leagues and his trajectory is unique. While not as legendary as the Anthony Davis growth spurt, things can change really fast when you grow 8 inches in two years. He was unknown even in France not too long ago. Up until like two weeks ago no one was saying he was better than Sidy or Rupert. It's confusing even some French fans who watch the youth levels closely.
I really think we're only at the beginning of his upward trajectory, but it's only fair to consider how far away he is right now. Offensively, he might be too raw for it to materialize into something great. But defensively I think he can come in and contribute right away. He's obviously got physical tools, but he was super engaged on defense when I watched him and he also has a knack for "doing stuff". One thing that was super disappointing about Exum is that he never super active. Didn't get a ton of rebounds, steals, deflections etc. When your offensive game is so raw you've got to find other ways to contribute. While both were hesitant to shoot, Exum kinda stayed in the corner praying he didn't have to shoot an open 3. Bilal is at least cutting, crashing the glass, and looking to push whenever he creates a turnover or gets a defensive rebound. There's no softness to him.
That's a lot of words to say that Bilal's mental game looks MUCH better and I would also say that he is way more impressive as an athlete. It's not just his vertical, his footwork on eurosteps and dexterity in the air is crazy. Makes it look easy.
I still think his most likely outcome is a McDaniels/Herb Jones type. Someone who is a complete defensive menace and does just enough to stay on the court. He has the upside to be much, much more on offense but it will take a ton of development. Defensively I think he's actually one of the safer picks in the draft. The defensive tools and mentality are in "can't fail" territory.