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.

I don't want to defend gulags but they didn't have poison shower rooms or child corpse disposal staff.

Neither did concentration camps:

"Interned persons may be held in prisons or in facilities known as internment camps (also known as concentration camps). The term concentration camp originates from the Spanish–Cuban Ten Years' War when Spanish forces detained Cuban civilians in camps in order to more easily combat guerrilla forces. Over the following decades the British during the Second Boer War and the Americans during the Philippine–American War also used concentration camps.

The term "concentration camp" and "internment camp" are used to refer to a variety of systems that greatly differ in their severity, mortality rate, and architecture; their defining characteristic is that inmates are held outside the rule of law. Extermination camps or death camps, whose primary purpose is killing, are also imprecisely referred to as "concentration camps"."

https://en.wikipedia.org/wiki/Internment

Don't minimize the Holocaust on your way to agree with everyone else that tankies are delusional assholes.

The singularity of the Holocaust lies in the extermination camps, where millions of people were murdered with industrial efficiency:

https://en.wikipedia.org/wiki/Extermination_camp

Saying that concentration camps exist(ed) in other countries is not Holocaust relativism.