The history of Stalin times in Soviet Union is trully horrific. It's worth knowing just to be aware what kind of hell can be arranged on a mass scale by an evil dictator. It should be taught in all schools across the world, along with the deeds of other XX century evil mega mass murders.
For learning more, I personally recommend starting with "Kolyma Tales" by Varlam Shalamov. Aside from the educational part, it's a great piece of literature.
Varlam Shalamov is a master of short form, although IDK how well his stories translated.
About educational part: it's a frequent misconception.
"Kolyma Tales" are not autobiography, it's a fiction.
E.g. His depiction of thieves wars reads as documentary but it's not. There is not a single personage that has direct match in reality. For some: it looks like combination of several real persons, some has no real analogues.
The same with events, chronology and geography.
To write a documentary was never the goal for Shalamov.
And keep in mind that it's a perception of Shalamov who always was a man of weak health.
Dostoevsky was in similar or even harsher conditions but he found the strength to see in criminals around him not only infernal bad.
If you suppose that Dostoevsky is not relevant: there are other authors with similar experience.I
For example: Ahto Levi, Estonian, Hitlerjugend on start of WWII, conscripted in SS near end, after war - criminal, repeat offender, member of nationalistic gang -he's one of thieves that Shalamov depicts.
His "Notes by Gray Wolf" shows both degradation to beast and then return to human.
For learning more, I personally recommend starting with "Kolyma Tales" by Varlam Shalamov. Aside from the educational part, it's a great piece of literature.