I was wondering why 100% is not a category for both 3D World and Bowser's Fury. 100% for 3D World would probably be 380 stars, 85 stamps, and gold flagpoles for every character.

Also, 100% for both games would be 100% 3D World + 120 shines.

100% in sm3dw is a thing in the category extensions
https://www.speedrun.com/sm3dw_bfce#Super_Mario_3D_World

bowsers fury, well, is alredy a thing in the main
the game only has 100 shines lol

and about complete 100% of both summed up
we also have in the main "480 SS"
is basicaly 380 stars + 100 shines
380 is actualy pretty close to 100%, this last is basicaly because of the characters stuff like 380 shines x2 right (because of needing stamps for the very last world anyways)
thats why the moved 100% to the category extensions, wanted to mantain it as the total completion, but isnt that relevant
so summing up 100% + 100 shines would definitely be in category extensions, and someone has to be interested first for something like this

yes defo would be a category extension