I read it on bakatsuki, but sadly, it was licensed recently. I cant give you the link as only agregator has it now
"No. 6" - I read it for the BL, but I was shocked by how thought-provoking and upsetting it was. The author was really harsh and unforgiving in their search for honesty, but they also aren't negative for the sake of being negative. It's definitely a series that was written to find answers.