Stalin alone:
https://en.wikipedia.org/wiki/Joseph_Stalin
Conversely, his totalitarian government has been widely condemned for overseeing mass repressions, ethnic cleansing, executions, and famines which caused the deaths of millions.
https://en.wikipedia.org/wiki/Excess_mortality_in_the_Soviet_Union_under_Joseph_Stalin
This contained official records of 799,455 executions (1921–1953),[8] around 1.7 million deaths in the Gulag,[9][10] some 390,000[11] deaths during the dekulakization forced resettlement, and up to 400,000 deaths of persons deported during the 1940s,[12] with a total of about 3.3 million officially recorded victims in these categories.[13] According to historian Stephen Wheatcroft, approximately 1 million of these deaths were "purposive" while the rest happened through neglect and irresponsibility.[2] The deaths of at least 5.5 to 6.5 million[14] persons in the Soviet famine of 1932–1933 are sometimes, though not always, included with the victims of the Stalin era.[2][15]
Ubuntu was once an okay-ish distribution, many many years ago. Then Canonical got rogue, made some very sketchy and irritating decisions (walled garden, snap, advertisements with Amazon, now advertisements in their package manager, ...... so much more)
Ubuntu is the bane of Linux. Use upstream Debian if you like apt; Linux Mint for an easy entry; Arch, if you're quick of wits and want to widen your knowledge and skillset.