Strictly speaking, Malenkov resigned in favor of Bulganin (who became Prime Minister), not Khrushchev. But the resignation did show that the office of Prime Minister had become distinctly secondary, that of CPSU First Secretary far more important.
And in his final months as Prime Minister, it was Malenkov who favored more "liberal" policies with respect to (1) German reunification and (2) consumer goods vs. continued emphasis on priority for heavy industry. On both issues, Khrushchev took a more hard-line stance (though at least with respect to the consumer goods issue, this may simply have been an opportunist move to get the support of Stalinists like Molotov and Kaganovich against Malenkov). See
https://www.alternatehistory.com/fo...r-denuclearized-germany.455656/#post-17875486 for Malenkov's position on German reunification. Khrushchev later told Walter Ulbricht: "Malenkov and Beria wanted to liquidate the GDR, but we fired one and shot the other..."
https://books.google.com/books?id=2bEYCgAAQBAJ&pg=PA41 On consumer goods, note that Khrushchev in January 1955 stated that the theory that heavy industry need no longer be given precedence over consumer goods was "a belching forth of the right deviation, a belching forth of views hostile to Leninism, which in their time were preached by Rykov, Bukharin, and their ilk."
https://books.google.com/books?id=DxyF5gGdclUC&pg=PA128 It's a little bit unusual to give Rykov first place in a listing/denunciation of "Rightists" but Khrushchev was probably making the point that Rykov, like Malenkov, had been Prime Minister of the USSR...)
The fact that in 1957 Malenkov, the hard-core Stalinists Molotov and Kaganovich, the relative "liberal" Shepilov, and Bulganin (who claimed that he had no ideological differences with Khrushchev on issues like the reorganization of industry, the Virgin Lands program, etc.) all joined together in an attempt to oust Khrushchev says something about how opportunistic leading Soviet politicians could be, and how polarizing a figure Khrushchev was.