It's really interesting how much the writing process differs among people. I could never see this working for me. 95% of my writing is getting to know my characters and accurately recording what they do, 5% is actually having a plan on what I want to happen to drive the plot. Getting to know a character is like getting to know a person, except instead of interacting with them and hearing their words IRL I'm "watching" them go through experiences in their life and "hearing" their thoughts instead of just their spoken words. Me writing the story feels more like me just channeling these imaginary people and recording what's happening to them, sometimes recording it in their own words. It's almost like running a tabletop campaign, where I'm setting up the environment and the major problem but then leaving it up to my players to drive the action and give me hooks to use.

This leads to a lot of pacing problems that I have to solve when editing, and a really inconsistent rate of progress on the initial draft (lots of days spent just trying to "hear" what happens next) so I've tried a lot of plans like this to make myself a better writer. But every time I've tried I've come up with nothing. I don't know the characters, so how can I possibly plan out what they're going to do? I can't fill out a spreadsheet about them either, because I don't know anything about them yet, how do I know what the right answers are to put down? The only exception I've found is when I write a bunch of short stories and/or scenes outside of the longer novel from their POV and get to know them that way, then I can fill in the character worksheets and figure out what they would do and write down the scenes in one sentence or less summaries a long time ahead of time. I get that writing scenes involving them is logically making stuff up just as much as picking personality traits to fill in the blank in a worksheet is, but it doesn't feel that way. It feels like I'm an observer.

Disclaimer: never had anything past a short story published by anyone other than myself, so I'm not exactly an authority. It's definitely not an efficient style, but it's how it works for me.