This is a tricky question. Of those you linked, I'll give it a go of ranking them with my reasons for where they stand.
1. Onyeka Okongwu: I think he projects to be the best big-man defender of the draft. He's still a teenager, has the physical length and strength to cover most 4s and 5s, he was productive in college, he's athletic enough to defend the perimeter. He's also a strong rebounder, which is an integral part of finishing defensive possessions.
2. James Wiseman: Wiseman has the highest potential IMO. He's got the best NBA physical profile - he's longer, taller and heavier than AD and Nerlens Noel were when they got drafted - and he showed good defensive instincts in his very limited college minutes. If he'd played an entire season of 3BPG with only 1.7 fouls a game he would probably be a lock for top 2.
3. Xavier Tillman: Tillman probably has the highest defensive IQ of the bigs in this draft. As an MSU defensive-oriented big who is a good passer he'll always be compared to Draymond Green, and if I'm him I would try and take as much from Draymond's game as possible. He's bigger than Draymond, and I could easily see him developing into an elite defender if he's drafted to a team that uses him well.
4. Paul Reed: I love Paul Reed's defensive ability. I don't share the concerns of some regarding his strength. His hustle is unreal, his reflexes are really fast and his defensive instincts are great. His per-minute defensive numbers were awesome every year. I think defensively he'll pan out like a better Jerami Grant - elite at defending 3s and 4s and capable of defending 5s. He might never be suited to covering Embiid or Jokic.
5. Precious Achiuwa: All the athletic tools an NBA front office could want. He's older and doesn't have too much experience playing the 5, but his athleticism will let him comfortably cover 3s and 4s. If he gets the right coach he could be a terror defensively.
6. Patrick Williams: I think Williams is more suited to wing defence, but he's super young and a super athlete, so if he grows an inch or two (not unheard of) he could immediately become a nightmare on defence. However, he's incredibly raw on both ends and is a very long-term project.
7. Jalen Smith: Good athletic shot-blocker, but I don't particularly like what I see in his perimeter defence. He needs to add some strength if his perimeter defence is going to be weak as he could be prone to abuse inside from the true big men like Embiid.
8. Tyler Bey: I don't think Bey will have any ability to defend the guys you listed as he's so slightly built and is turning 23, but he'll be a really solid wing defender I think.
Honourable mentions:
Udoka Azubuike - could be a great situational big defender for the NBA brutes.
Isaiah Stewart - 7'4" wingspan, 250lbs, light on his feet, all the physical tools.
Daniel Oturu - NBA-level length and was a really good college level rim protector, reminiscent of Whiteside.
Nick Richards - elite size and length (7' with 7'5" wingspan), good defensive instincts.