My previous method was to just fill in a plot outline template for a 3-act story. Then I tried a Save The Cat! Template and both seemed like they don't map very well to a web novel style of writing.
They (those outline styles) are obviously tied to the traditional publishing model, where every little thing is meant to conclude by the end of say, 80,000-120,000 words. With zero consideration of things like world maps, systems (so you can keep track of say, leveling), etc.
For litRPG, I want more. In fact, I need more. Otherwise I'll write a chapter and realize that character X hasn't even earned the skill necessary to complete the plot yet!
I plan to use a new publishing platform that I invented/coded to publish this story too, which accepts Obsidian export. So when the story is complete, I can export the parts I choose and it'll sort of have a built-in wiki along with notation for a world map (so the reader can check the progression while reading the story; it's in the sidebar and reveals more of itself as the story goes different places).
I already wrote the publishing platform, so now I'm working on "the example story" that shows off the features. The biggest one is being able to pull up the sidebar to view the characters current profile info (which includes their stats, levels, etc).
Example: When you read that a character just leveled up [Screaming Internally], that will be reflected automatically in the sidebar. In the text, it just uses Obsidian call-outs for that so it's pretty native/natural.