There is something i noticed about the 4 Supernova that tried to attack Big Mom which is …
In The Seducing Woods we learned from Brûlée that 4 Supernova tried to attack Big Mom who are Kid, Apoo, Capone and Urouge.
As we all know reaching Whole Cake Island is pretty hard and one must get past a lot of security and islands before reaching there, Luffy got there with the help of Pudding but what about the other 4 Supernova !!!
I find it interesting that all 4 seem to have abilities that helped them reach it:
Kid have a magnetism DF and it seems that he can use it to detect islands and that’s how he evaded all other islands until he reached Whole Cake Island.
Apoo have DF related to music and sounds and it seems he can use it to send signals and detect objects in this case islands like a sonar and that’s how he reached Whole Cake Island.
Capone being a master tactician and surely having many ties to the Underworld where he possibly got valuable info definitely contriubted to him reaching the island undetected.
Urouge is from a sky island (Possibly Birka or Skypiea or other) and when Kaido tried to suicide from a sky island, Urouge was shown to be there suggesting that he have means to ascend and descend from that island, so possibly Urouge was able to reach Whole Cake Island from above.
It all these prove true, it means that these Supernova are capable of entering most islands and places, showing how dangerous Supernova are and how they are truly rivals of Luffy not just in strength.
*Theory by Salah Eddine Bouhank