For me personally, I garner absolutely no enjoyment of world-building for the sake of world-building. To me... spending hours upon hours trying to come up with entire regions of "stuff" that end up never getting used is such a waste of time that I wouldn't DM D&D at all if I was forced to do so.
I'm much more a story-focused DM. I care about the player's experiences engaging with the area they are in and their personal place and stakes within it. Everything I put in front of them is for their benefit as characters. To me, "sandboxes" are pointless. That's creating a whole crapton of areas that are completely worthless to the game if the players gain nothing from engaging with it (either because the areas are too low-level to be uninspiring cakewalks or so high-level that they are guaranteed to be TPKs).
I am the opposite. I LOVE world-building and for me developing adventures and storylines runs parallel with that work. We may not always get to all the possibilities but that is okay because I start with outlines and skeletal structures, a few named NPCs and then develop an area more as it seems like the PCs will be going there.
Since I tend to run multiple campaigns in the same setting, this also means that whatever doesn't get used in this game can be used in some future one, and the actions of the PCs in this game can influence the world being played in the next game.
Heck, even if it is not the same setting, I just grab stuff from older ones and file off the serial numbers. For example, in my Ghosts of Saltmarsh game, I took a place I never got to fully develop in my old homebrew and just yanked it out and built a new setting around it - thus making use of some past work, but also shaping it for the current game.
For me, running a campaign is world-building, because what is a world if not a story about the world and the people in it?