Prison labour should be limited to apprenticeships in order to teach prisoners new skills to reinsert into society. And under no case forced under the threat of i.e solitary confinment.

The way it works in the US is the best way to release people that will instantly get into crime again due to leaving prison with nothing and having no possibility to gain money legally + a potential gigantic debt on the back of their family

Prison should be a place where criminals learn to live normally in society and go back on the right path, find a job, etc, not an institutionalized racket scheme that produces even more desperate and impoverished people who will not change anything about their way of life and keep doing nasty business with the help of all the new acquaintances they made there.