I highly recommend the book “nothing to envy”. It is a series of first hand accounts from N. Korean defectors/escapees. Truly unimaginably bad.

In that theme, I’d also recommend D-Day Through German Eyes (short), as well as Second-Hand Time (long). Both are also a collection of first hand accounts. The former is the experiences of the German soldiers during the D-Day offensive and their beliefs in their actions at the time. The latter is experiences of the fall of the Soviet Union (a fascinating read, but also the most harrowing and emotional book I have ever read)