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’m a simple person, I see DokuWiki and I install it some plugins. Easy to self-host on a cheap VPS (no database required!) or on your own machine (if you have access to eg.:Docker). But that’s more for a general wiki kind of thing, useful but not specialized like having tools aimed for worldbuilding.
Haven’t checked any of the offerings here but I’m told by a couple fellows that they’ve had decent story with Hammer. Would probably start looking there.