I studied modern German history with a minor in German language for my undergrad degree.
The difference between the Holocaust and the Soviet gulag system is the mechanization of the modern state, Germany, which was dedicated and harnessed solely to murder.
Concerning the gulag system, I recommend Aleksandr Solzhenitsyn's The Gulag Archipelago, which demonstrates that the gulags of all types were designed first and foremost as a labor system, regardless of how destructive it was.
For instance, The White Sea Canal was built with zhek labor who were only issued hand tools to construct it. Only one ship ever traversed it, Stalin's, for its opening. And even then it had to be specially constructed with a shallow draft due to the minimal depth of the hand constructed waterway.
The Nazis, on the other hand, established, operated and later partially destroyed Auschwitz with Chelmno, Belzec, Sobibor, and Treblinka which were termed Vernichtungslager, or extermination camps, wholly designed to murder and then turn to ash vast incoming volumes of humanity. The massive amounts of generated ash at Auschwitz was dumped in the Sola River which ran near the camp.
This operation, called Aktion Reinhard after the assassination of Reinhard Heydrich of the SS in 1942 in Prague by Czech operatives, perfected over the years by individuals like Rudolf Höss, the next to the last commandant at Auschwitz. Höss was brought back from the concentration camp inspectorate by Heinrich Himmler, the Reich leader of the SS and Police, especially because of his previous success in mass murder in order to rapidly gas with Zyklon B, a cyanide derivative usually employed to fumigate and kill rats and mice, and then cremate the 438,000 Jews from Hungary.
Here are some statistics from 1944 at Auschwitz alone to give you the scale of the SS murder operation.
- 16 May – The railroad siding, which is located just inside the camp is released for use. It permits deportees to be taken from the train, selected for the gas chambers and then transported directly to Gas Chambers Nos. II and III at Auschwitz II-Birkenau. The start of deportation to Auschwitz of almost 438,000 Jews from Hungary.
- 10–12 July – Liquidation of the so-called Theresienstadt family camp. The Nazis murder about 7,000 Jews in the gas chambers.
- August – Start of deportation to Auschwitz of 67,000 Jews from the ghetto in Litzmannstadt (Łódź) in Poland.
- 2 August – Liquidation of the “family Gypsy camp” – the SS murder almost 3,000 Romanies (Gypsies) in the gas chambers.
- 12 August – Start of deportation to Auschwitz of 13,000 Poles, arrested en masse after the start of the Warsaw Uprising, which was crushed by SS troops. The commander of the operation, Jürgen Stroop, had a book made about this Action, entitled Die jüdische Wohnbezirk in Warschau ist kein mehr - The Jewish living quarters in Warsaw is no more.
Operations at Auschwitz ceased in November of 1944 as the Red Army approached Silesia where the camps, Auschwitz, Auschwitz II - Birkenau and Auschwitz III - Monowitz, were located.
Of the 1.3 million deportees who arrived at Auschwitz, 1.1 million, or some 85%, were murdered shortly after their arrival, often within an hour or two.
Read the following, in any order you please, in an attempt to grasp the scope, scale and management of this murder of men, women and children:
books by Primo Levi.
The War Against the Jews by Lucy Dawidowicz
The Rise and Fall of the Third Reich by William R. Shirer - particularly the section captioned "The New Order"
Twelve books selected about the Holocaust: https://www.panmacmillan.com/blogs/history/the-best-books-about-the-holocaust
Another 12 books on the Holocaust: https://www.rd.com/article/holocaust-books/
The trial documents on Adolf Eichmann
The Holocaust: The Jewish Tragedy by Martin Gilbert
The Master of Auschwitz: Memoirs of Rudolf Höss
Books on Josef Mengele - https://www.goodreads.com/shelf/show/josef-mengele
The Theory and Practice of Hell by Eugen Kogon
The SS: Alibi of a Nation by Gerald Reitlinger
The Waffen SS by George Stein
Soldiers of Destruction by Brian Sydnor
There are two motion pictures I urge you to see: Shoah directed by Claude Lanzman, which covers the Holocaust in nine hours, and Conspiracy with Kenneth Branagh, which explains The Wannsee Conference in January of 1942, which established the elements and the coordination for solving the "Jewish question" in occupied Europe.
I was fortunate enough to have directed studies with visiting professors Carole Fink of The Ohio University and George Stein of Cornell while I was studying German history at SUNY Binghamton. My undergrad advisor and thesis director was Prof. Dr. Dietrich Orlow at Boston University, who has written extensively on the Nazi Party.
If I may answer any questions or direct you to sources, feel free to ask.