Looking for books that involving such deep friendship that stay with me after the last page

I’m looking for a book that I’ll make me feel genuinely sad when it’s over, like I’m parting with close friends.

I’ve realized my favourite stories are the ones with deep, meaningful friendships where you feel like you truly know each character and belong in their world.

Any genre is fine (non-fiction is acceptable too), just nothing horror! I still want to shower in peace.

Give me your best recommendation (don't give me lists of long selection). Thank you in advance!