I've had a lot of success using Obsidian for managing and organising information (both for campaigns but also just in general).

You can link to other pages in your notes, there's a canvas feature if you like that sort of thing and my personal favourite, the graph, where you can see how all your pages connect to eachother.

It also has a lot of community plugins some of which are useful for campaign stuffs like Obsidian Leaflet(maps) and Fantasy Statblocks.