Wanting to get into non-fiction as a heavy fantasy /sci-fi reader, but my brain is not happy with it.

If anyone has non-fiction recommendations for a lifetime fiction reader please comment below with them. I really want to start reading non-fiction and spend my reading time differently than I have all my life. I have read almost exclusively sci-fi and fantasy all my life. Sprinkle in required reading for school and that’s about it. [...]