I heard of a few wikis and desktop apps which are FOSS, some has UI’s which look a bit old for, there are a few things like logseq I might try but from trying for a bit, i dont know how suitable it is for my usecase, but I want something that would be more specialized or at the very least have features that would be amazing for world building, (on a desktop app preferably but self hosted works too), like timelines, references to other pages, common stuff like Tags, Categories, and Taxonomies, graph view potentially, good search, templates. I don’t need all the features I listed, just some or what your think aligns with what I am looking for.
I may have missed something, here so to make sure:
It can also help you write the actual book, worrying about the document ‘look’ aka its formatting is optional (and if done properly, using Styles, it’s almost 100% automated) ;)