To be clear - strong disclaimer - not questioning the Holocaust.

Trying to understand if there is a correlation between the revision of the Auschwitz numbers from 4m down to "at least 1.1m" in 1990 and the total Jewish death toll in the Holocaust.

In the wiki on the Holocaust this is the opening phrase of the Jewish victims section :

Since 1945, the most commonly cited figure for the total number of Jews killed has been six million. The Yad Vashem Holocaust Martyrs' and Heroes' Remembrance Authority in Jerusalem, writes that there is no precise figure for the number of Jews killed, but has been able to find documentation of more than three million names of Jewish victims killed, which it displays at its visitors center. The figure most commonly used is the six million attributed to Adolf Eichmann, a senior SS official.

In the same section the number that is cited for total Jewish deaths is 5.93 million - and the source is Dawidowicz, Lucy. The War Against the Jews, Bantam, 1986. p. 403

If the total number is based on a work published in 1986, then why wouldn't that number have been revised following the reduction of the Auschwitz number?

Here is the death toll excerpt from the Auschwitz wiki

The exact number of victims at Auschwitz is difficult to fix with certainty, as many prisoners were never registered and much evidence was destroyed by the SS in the final days of the war. As early as 1942, Himmler visited the camp and ordered that "all mass graves were to be opened and the corpses burned. In addition the ashes were to be disposed of in such a way that it would be impossible at some future time to calculate the number of corpses burned."

Shortly following the camp's liberation, the Soviet government stated that four million people had been killed on the site, a figure now regarded as greatly exaggerated. While under interrogation, Höss said that Adolf Eichmann told him that two and a half million Jews had been killed in gas chambers and about half a million had died of other causes. Later he wrote, "I regard two and a half million far too high. Even Auschwitz had limits to its destructive possibilities". Raul Hilberg's 1961 work The Destruction of the European Jews estimated the number killed at a maximum of 1,000,000 Jewish victims, and Gerald Reitlinger's 1968 book The Final Solution estimated the number killed at 800,000 to 900,000.

In 1983, French scholar George Wellers was one of the first to use German data on deportations to estimate the number killed at Auschwitz, arriving at a figure of 1,471,595 dead, including 1.35 million Jews and 86,675 Poles. A larger study started by Franciszek Piper used timetables of train arrivals combined with deportation records to calculate at least 960,000 Jewish deaths and at least 1.1 million total deaths, a figure adopted as official by the Auschwitz-Birkenau State Museum in the 1990s. Piper also stated that a figure of as many as 1.5 million total deaths was possible.

I have seen different interpretations of this data. One theory is that the Soviet number of 4 million was used to exagerrate Polish deaths in the camp. If this is accurate would this have been done to cover up the Katyn massacres? Why would the Soviet gov't have done this?

I am confused by this situation and have seen Holocaust deniers use arguments based on the revised Auschwitz numbers - can r/askhistorians bring something to the table?

Link to death toll section of Auschwitz wiki

Link to victims and death toll section of Holocaust wiki

PS : Dear mods - I understand wikipedia is not a source in itself - I am posting the links to the pages I am quoting for reference