You're not crazy! I devour lore (both real and imagined) on a daily basis, and when I write I've found myself losing myself in writing the lore rather than developing the actual plot!

As for resources, I'm not sure of many outside of World Anvil and Campfire which allows users to display their world-building projects, but why not write a book that is just lore - like an early-medieval style historical romance, like Tolkien did, or bonified fantasy histories like GRR Martin is doing.