Just for information the death count of gulags is largely unknown. Russia itself says its 1 million but pretty much all other sources say its too low to be even believable. There are credible sources for 1.5 to 8 million deaths (also non-credible sources that go much higher). Unfortunately unlike the nazies, soviets did not really have record keeping at all so all sources are estimates based to prisoner and guard writings. Another factor that makes estimates hard is the practice of when a prisoner was near death they would be shipped home, a lot of those never made it home but don't count as killed by a gulag.

There was also mass deportations from satellite states that weren't sent to gulags presumably but that's a different thing.