Musical theme: Kahlil Gibran wrote an eloquent essay on music, though good luck finding it.
Outside your comfort zone: Capitalism as Civilisation by Ntina Tzouvala, a theoretical work which examines how western legal scholars categorized non-western polities based on a racist standard of civilisation and justified colonising them.
Book from a different cultural background: the Cairo Trilogy by the Egyptian author Naguib Mahfouz, a chronicle of a wealthy family witnessing the instability of the 1930s in British-occupied Egypt.
As for a book from a different cultural background, I remember reading The White Tiger by Indian author Aravind Adiga about 10 years ago and really enjoying it.
Outside your comfort zone / different culture: The Last Ringbearer by Kirill Yeskov. It examines the events of The Lord of The Rings, from the perspective of Mordor and the orcs. Written by a Russian author. Super good, almost better than LotR.
As a suggestion form me (a random on the internet) ultraprocessed people, the science of food that isn't food.
You could read Let's Talk About Love: A Journey to the End of Taste by Carl Wilson.
It's an essay(ish) book about taste in music, funny to read and not too long (~200pg I'd say).
About the comfort zone, you could try and read something about contemporary problems and predicaments. A poison like no other talks about plastics in our everyday life (not fun), or something really old like Seneca's On the Shortness of Life: Life Is Long if You Know How to Use It (~100pg)
Maybe Storm In a Tea Cup by Helen Czerski for a book outside your comfort zone. It's quite the interesting exploration of the principles of physics that underpin the world around us.