This was an interesting investigative/prison story. The concept was original, clever and well executed.

However, it has A LOT of triggers - violence, racism, transphobia, threats of rape, mis-gendering.
It get that it's a prison and there's a lot going on, with some complex gang turf war stuff happening in the background, but a lot of things felt like gratuitous violence just for the sake of it. (This was especially true of later volumes)

So, while I found the crime aspect interesting, the plot wavered into pointless prison politics at times, even sometimes drifting into lectures about the American prison system.

I also found it strange that there's a bonus story at the end, which is apparently taken directly from the original source light novel. I'm not sure why this choice was made, but it didn't really add anything to what was included in the manga version, IMO.