All true, except both Philly and Charlotte have holes to fill and a top four pick gets you a valuable commodity. It might be different if Khaman was a consensus top four pick (though actually it might not), but why
reach for a duplicative pick when you can fill a hole and hope your existing high-level (when they play) option can play a full season?
Especially the Sixers. If they want to compete in the short term, they have to rely on Embiid. It would be crazy for them to use the #3 pick that kind of fell into their lap to draft a backup center. Even if they decide Embiid is done and they have to go for a ground-up rebuild, I doubt in this day and age they'd decide to rebuild around a raw, defensive-minded center. As far as San Antonio, as
@godins said, they're taking Harper. There's pretty close to a zero percent chance they decide to take Maluach with the #2 pick. Which leaves Charlotte. That team is in such bad shape, they have to take the best available player. If Ace Bailey is really 6'7.5", like his combine measurements said, I'm not sure there's much practical difference among the #3 through #8 picks, so maybe Charlotte decides the best available player is Maluach. But I'd be very surprised if they did.
If one of these teams trade their pick, then that could be a different story, but for whoever said Khaman might "invade the top four," if you have to assume a trade in order for your prediction to occur, then it's a waaaaay-out-there prediction.