The death toll of Capitalism is a negative number.

Poverty worldwide included 94 percent of the world’s population in 1820. This number was reduced to 17 percent in 2011. The largest part of the fall of poverty took place between 1981 when 53 percent of the world lived in poverty and 2011 when the aforementioned 17 percent did so. This rapid fall is largely due to the onset of industrialisation which in turn was made possible by the availability of the capita needed to build the mines and factories. While it may have been a rough ride to start with - working conditions in early capitalism were atrocious - this was eventually solved in western countries due to regulation and enlightened self-interest. The same cycle has taken place in non-western countries where working conditions sometimes more resemble those in the early industrialised west.

Capitalism with regulations is still capitalism, no matter whether that be European- and North American-style big-state capitalism or Deng Xiaoping's Chinese state-regulated capitalism.

Now about those examples you gave:

On the death toll of the Atlantic slave trade here's some numbers courtesy of Statista [1]. From 1501 until 1866, it is estimated that the transatlantic slave trade saw more than 12.5 million African people forcefully put on slave ships and transported to the Americas. Of these 12.5 million, only 10.7 million disembarked on the other side of the Atlantic, meaning that approximately 1.8 million (14.5 percent) did not survive the journey, known as the Middle Passage.

The principal cause of the Bengal famine - with a death toll of around 3 million people - was the epidemic of Helminthosporium oryzae (a plant disease affecting rice crops), an epidemic only matched by the Irish potato famine of 1845. This was exacerbated by poor regional administration and the war with Japan [2].

The potato famine was caused by an infestation of Phytophtora infestans (potato blight, a crop fungus) which was exacerbated by the fact that only a single variety of potato was grown in all Ireland in combination with inadequate (the repeal of tariffs on grain products, import of corn from the USA) and counterproductive (continued and sometimes even increased export of food products from Ireland to Great Britain) government responses. The death toll of the Great Famine is estimated to be up to 1 million people.

The death toll of the colonisation of the Americas (north and south) was largely due to diseases like Smallpox which had been chronic in Eurasian populations for hundreds of years but to which native Americans did not have any acquired immunity. It is important to realise that the Spanish and Portuguese and French and British and Dutch (etc.) did not know about the dangers of these diseases to the native population when they landed on the shores of the Americas, this was not some plot to eradicate the native population. It was also not related to Capitalism which only became a thing some 400 years later. As to the numbers involved this seems to be disputed but they are indisputably large, probably in the tens of millions. The number of native Americans killed in combat by westerners in the 'Indian wars' in the United States is far lower, around 30.000. Most importantly, none of this has anything to do with Capitalism unless you want to equate all types and wars of conquest with Capitalism in which case Genghis Khan was the greatest capitalist of all.

[1] https://www.statista.com/statistics/1143458/annual-share-sla...

[2] https://historyreclaimed.co.uk/the-bengal-famine-what-the-ex...