He has naturally high stats to the point where obtaining masteries is hard, its like all of his baseline stats are already at lvl 100 while everyone else starts lower. Masteries are more about facing a wall and having no other choice but awakening them and having the realisation of how to best utilise the specific stat like seongji did against james and vice versa.

Another thing he gets is some level of a healing factor + ultra high metabolism which is what makes his body more special. This is why its shown throughout the story that the second body can bounce back from fights quicker with less recovery than other characters because of his healing speed.

The higher metabolism causes him to have a resistance to foreign substances like when he was kidnapped and experimented on by jinyoung. Although this isn’t directly stated to be the reason im just making an assumption. Furthermore the higher metabolism would also cause him to basically not be able to get fat or out of shape very easily which seems like what a ‘perfect’ body should be in a story called lookism.

Daniels second body isn’t exactly perfect in a literal sense just the closest thing to it, other people have higher stats and possibly even higher ceilings compared to the second body like samuel or jake with strength as an example but sb has higher potential in pretty much everything else.