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.
Seconding Fantasia Archive. It is probably the most feature rich FOSS Worldbuilding tool.
There’s also Hammer which is underrated imo.
WorldLoom is another one but currently undergoing a rewrite.
Although not specifically for worldbuilding, Manuskript is another option.
Wavemaker is another option but has optional AI.
Unless there’s readily available templates, you’d have to rework logseq a lot for this simple task imo. Take a look at mdSilo which is similar to Obsidian and with graph views. If you want something like Notion take a look at Appflowy or Affine but both are super into AI. If you’re fine with self hosting, there’s Colanode which is similar to Notion and into AI.