Stalin believed in the values of communism, he just also believed everyone was out to get him. Economically he followed Lenin’s plan of nationalization and collectivization even more zealously then Lenin would have. Lenin wasn’t as paranoid as Stalin and probably wouldn’t have killed and gulaged millions of “suspicious” people but he was still very much a dictator and was willing to use any means necessary to achieve his goals, same with Trotsky.
With any of them the super structure of the state and how it’s organized may vary a bit, but it would have all been built off a nationalized and collectivized base. Whether you want to call that base communism is up to you, but you can’t say one is and one isn’t.