Looking for Mind-Bending Sci-Fi With Cosmic Awe & Philosophical Themes

I’ml looking for sci-fi books that capture the vastness of space, the mysteries of time and existence, and a strong sense of wonder. I’m especially interested in stories that explore philosophical or existential questions, cosmic scale, strange civilizations, consciousness, humanity’s place in the universe, etc. Would love recommendations that feel awe-inspiring, haunting, mind-bending, or deeply [...]