His pragmatism, I think, wasn’t ideological just for himself. He had no loyalties himself beyond how it served him. If it served him, any of his loyalists would end up in the same death camps as everybody else.
That’s why he started out communism, became a fascist, and then worked toward becoming a communist again once he was secure in his power.
Stalin was much worse, though in that department. He’d have someone killed just because they were popular, see Sergei Kirov.
Stalin was distrustful of anyone associated with Leningrad, because he felt he couldn’t have the control there. He had most of the political figures associated with the Seige of Leningrad killed after the war.