I don't want to personally spend much time on 'what if we get a top 4 pick' questions. Nice to pretend, but even if ATL hovers around 8-9, the chances are slim.
That said, I think my top of the board is like:
Cooper Flagg
Dylan Harper
VJ Edgecombe
Ace Bailey
Tre Johnson
Kasparas Jakucionas
and then there's a drop. I can see Demin or someone getting next slot, but we're getting more into 'more questions' territory. Already with Tre you have him needing time to get his actions moving, questionable efficiency, and what else he brings. Kaspar has fallen off a tad, and his lack of athleticism, burst, bad handles, hurt him.
De'Aaron Fox changes things. We now have two players who will command around 18-20 shots a game in him and Victor. I don't know how a team factors a third high volume shooter (Harper, Bailey) or how those players do off-ball. Your creation is going to come primarily through Wemby and/or Fox. Castle will be a secondary facilitator in the main unit.
It's weird to talk about fit with a top 4 pick, but teams with a lot of talent (Houston, with Reed Sheppard) start talking about fit. This is why Edgecombe right now is my #2 on the Spurs board after Flagg. I think they're both players who don't need to be number one scoring options and probably are best if they don't have to be, but can be lethal operating away from other players' gravity. And then both have very high defensive potential. Of course Flagg is on another level, but even as Edgecombe is getting talked about more right now, I still think the Rutgers players are getting more oxygen.
So, yeah, with Harper, Bailey, and Johnson, a big question for me is what shots are they going to get, can they work off-ball, can they work as non-focal points. And then with either Flagg or Edgecombe you have your fourth starter who could slot in perfectly given the shot diets already getting established on the court and you just need your fifth guy.