Suggest me a heartbreaking book that’ll teach me important life lessons OR a historical/psychology/self-help non-fiction

I recently read "The Happiest Man on Earth" and I loved how it broke my heart then gave me hope while teaching me important life lessons. It was my first non-fiction book and memoir and it had me starving for more, so I'm looking for something similar and for general suggestions you'd give to someone getting into non-fiction. (You may recommend even the most well known books because I live under a rock.)

I really love history, so all the better if the book is historical. WW2, the Middle Ages, the Viking Age, just to name a few. Love European history, but feel free to recommend anything. I'm also willing to try out psychology, self-help, science, crime, more biographies and memoirs. But I'm mostly interested in the first three (history, psychology, self-help).

And bonus point if it's a bestseller thus widely available with multiple translations, because I'll be looking for a translation in my local bookshop. 😅 If it's not and in English only, I'd appreciate being told how easy of a read it is.