This one was more or less clear, even though I've read a lot of important books in 2024. Runner Up was “Was wird es denn? Ein Kind!“ (“What will it be? A child!“).
But Unlearn Patriarchy covers so many every day things that are based on patriarchal structures, that we don't even realise how they discriminate against other people. This book made me furious, I almost broke down in tears and it really openend my eys. Volume one was the same.