ahhh i love all of the world building asks you've been answering. it's just so fun to see how much work you've put into creating this cool (and slightly scary) universe. do you have this all figured out before you start writing or do you make it up as you go?
Answering worldbuilding asks is a lot of fun for me so I'm so glad other folks can enjoy them too
And I definitely don't have everything figured out when I start writing! I do both - I figure out some stuff, and then make up the rest as I go.
I generally don't do any plotting, but I will do some like...research / brain-storming on the structure of the world. I'm a big believer in creating 'forced paths' for characters so that their choices make sense. If people are putting themselves in bad situations, the world or their thought patterns have to force them in those situations, otherwise they wouldn't chose those bad situations and you end up with stories where a character is doing stuff where it's like 'well he's just too stupid to live, because no one would do that.'
So like, I needed there to be dystopian elements about Hillview. I needed Gary to be not trained in being an alpha companion. I needed views on secondary gender to be fixed etc. There's things I know I need in order to start kind of building out the scaffolding of a story.
I also work a lot within an app/program called Obsidian! I started using it last year or maybe the year before that, and it's helpful for me who likes to keep details of characters and some worldbuilding stuff, but isn't that interested in plot. Here's the current visual map for Underline the Rainbow! I didn't start fully fleshing this out until I was a few chapters in.
And here's an example of one of the files opened up (it operates like a Wiki)
You'll notice in the first chapter of Underline the Black there's actually very few details about what Hillview looks like, how it operates, Efnisien's back story, etc. It's all hinted at. This gives me space to keep fleshing out the world in the direction I want, and gives the reader time to experience a new world! So not having everything planned in advance is actually a really useful tool, if you can balance it with good hints/foreshadowing for more exposition later. :D
So yeah the answer to your questions is yes! I do both :D