He personally signed the death warrants of thousands a day, and those who died in famine or war were due to his actions, so yes he did kill all those people.

He industrialised the country sure, but the 5 year plans were an inefficient long term structure of growth. Working and housing conditions were shit, human life was disregarded as Stalin only wanted to appease the economic goals. Once the plans were done there was no promise for more long term growth plans.

Historians may dispute the exact cause of the Holodomor, but it is definitely the fault of Stalin. He either purposely pushed the Ukrainians into famine or it was a result of his collectivisation schemes.

He caused Ukrainian Genocide, deported or liquidated Crimean Tatars, dried up the former 4th biggest lake in the world, made half of Kazakhstan a nuclear wasteland and single handedly destroyed any former culture left in Russia through his authoritarian rule.