I think I should be more specific with my definition of bleak. It's possible to write a novel where the setting, and the story lead to dark places, and finish

I think I should be more specific with my definition of bleak. It's possible to write a novel where the setting, and the story lead to dark places, and finish badly for the heroes, but without the heroes giving up on life or thinking. There are many instances in history of people standing their ground in hopeless circumstances. In fiction, I think the best depiction of what I mean might be Letters from Iwo Jima (the movie, not the actual letters which are relatively sparse). Kuribayashi's character goes through hell consciously but his extraordinary resistance - down to refusing to banzai charge as is customary in those situations and instead patiently drawing out the fight to maximise enemy casualties, drawing out the pain for himself and his troops in the process - is a phenomenal description of character. It is specifically in Eastwood's depiction that this comes through although the real Kuribayashi was every bit the depicted one. So I do not consider the movie or the book "bleak" but incredibly awe-inspiring despite its content and ending for the protagonist. Meanwhile, the main character in Ubik and most of PKD's novels is continuously failing to have any agency, thwarted by unknown and unbeatable forces until he just accepts his fate and stops moving. I always thought that this book in particular and PKD's work in general were close to depictions of depression, which is where the bleakness is. I'm in a rush right now so can't immediately come up with a good example but many modern works of fiction depict wonderful conditions and stories with very bleak characters incapable of appreciating their luck.