Stalin did profess to care about the Soviet Union and Soviet citizens; his actions perhaps reflect this aspiration, however misguided. One caution I will offer is that it can both be true that Stalin was executed hundreds of thousands and ruled dictatorially, and on balance Soviet life was perhaps better on average that late Imperial life. Certainly as we slip into the 1980s and compare them to the post-Soviet 90s it would be fair to say that Soviet life was better than Russian life, but there is a counterargument there as well. I want to stress this point a little given the historic and contemporary debates surrounding communism -- there is of course no consensus.
Starting with things that are more clear: more than 1.5 million prisoners died in the Gulag; more than a million citizens were executed in purges, which began even before Stalin's rise to power and persisted after his death, peaking in 1937; hundreds of thousands of kulaks were executed in the early 1930s; more than fifteen million citizens were imprisoned during Stalin's reign; and thousands of scientists were executed for supporting genetics, eugenics, biocenology, "Jewish physics," and "Darwin-Weismannism."
But it's far from clear to me that Stalin had no interest in the Soviet citizenry or the ideals of the Soviet Union. It seems that he did genuinely subscribe to dialectical and historical materialism, and did view socialism as leading to a better future. Perhaps more importantly there are real accomplishments under Stalin in literacy, education, industrialization, and so on - but at the expense of indigenous languages, nature preservation, and workers' health. There, of course, are also major discordances in public statements and private beliefs. Stalin in 1931 professed to reject antisemitism, even founding the "Jewish Autonomous Oblast" of Birobidzhan, but personally held antisemitic views, forcefully relocated Polish Jews, and directly ordered the assassination of the members of the Jewis Anti-Fascist Committee. The imagined Doctor's Plot punctuated his effort to subdue Jews, especially following the foundation of Israel.
Stalin probably did legitimately believe in the promise of communism, but in a more abstract, aggregate way: the individual lives ruined may pale in comparison to the future promise of the Soviet Union.
While I am sure more can be said, I was able to find a related post that might be of interest to you.
In this post, u/restricteddata talks about whether Stalin really was "bad" and in answering this addresses the topic of whether Stalin cared about the USSR and its people.