Historical numbers vary, but I recommend checking historians using data from after the opening of the Soviet Archives. I also wouldn't count Pol Pot as a genuine Communist leader, and not out of any "no true Communism" nonsense, he legitimately denounced Marxism and had a form of "Communism" utterly divorced from the Marxist canon.

One thing to keep in mind is that extremely frequently, deaths due to natural forces like drought-induced famine or otherwise are counted as "excess" deaths, which is a dishonest framing. No genuine Marxist would say there were no excess deaths in Socialist states, such would be taking an idealist analysis that infantilizes the genuine revolutionary struggles faced internally and externally by the proletariat. However, we do affirm that historical evidence overwhelmingly favors the Communist assertion that excess deaths were rather minimal when compared to peer Capitalist nations.

It takes critique based on material reality, not propagandized mythology, in order to correctly contextualize what went right and what went wrong in historical applications of Socialism, so that any future excess can be minimized to the best of our abilities. To adopt the bourgeois line is to adopt the stance that trying to implement Socialism is inherently evil, thus we must shed light on history and take a genuine critique, one that is proletarian in perspective.

Somewhat poetically, the rhetorical battleground for future and present Socialism is often rooted in historical interpretation of Socialism's practice. That's why historians play a vital role in fighting for a better world.