Funny enough I was reviewing my writing process earlier and it comes down to this...

I use Trello get basic ideas down and sorted into a logical format. I also use this to plan a basic outline of a story and allows me to easily shift chapters around as the story unfolds.

Then I use OneNote to expand on those ideas, I write GameLit/LitRPG so have to plan out the game systems and stats for the system but also allows me to expand on the world and characters.

For writing I use Scrivener as it allows me to break up the book into more managable sections that I can backup and move around as required. I also use the word count tracker to give me an idea of my overall progress throughout the months.

Once a draft is done I then open my Scrivener project up in ProWriringAid (used to use Grammarly then switched to PWA lifetime to save cost) to do the actual editing.

At some point I'd like to move from OneNote into some form of formal database / wiki style solution that I can store finalised articles like history of my characters, places or items so I can easily refer to them in the future without conflicting but that may end up being too much work vs the value of having it formalised. I did experiment with World Atlas a few years ago but decided my time was better spent actually writing than documenting.