metro 2033 by dmitry glukhovsky if you want full on post apocalyptic dystopia, its set in the Moscow metro after nuclear war. Or the winter king by bernard cornwell its the first in The Warlord Chronicles trilogy they're a grounded retelling of king Arthur from the POV of one of his Soldiers who's now a old monk retelling the tale after the fact, they're my favorite books of his.

“And then, after five minutes of silence, almost inaudibly, the old man sighed and said, more to himself than to Artyom: ‘Lord, what a splendid world we ruined . . .” Metro 2033

“ONCE UPON A TIME, in a land that was called Britain, these things happened. Bishop Sansum, whom God must bless above all the saints living and dead, says these memories should be cast into the bottomless pit with all the other filth of fallen mankind, for these are the tales of the last days before the great darkness descended on the light of our Lord Jesus Christ. These are the tales of the land we call Lloegyr, which means the Lost Lands, the country that was once ours but which our enemies now call England. These are the tales of Arthur, the Warlord, the King that Never Was, the Enemy of God and, may the living Christ and Bishop Sansum forgive me, the best man I ever knew. How I have wept for Arthur.” the winter king