Stalin wanted a national anthem in the closing days of World War II because the Communist “Internationale” was embarrassing and reflected a country in revolution.
It wasn’t fitting for a nation-state and needed to be changed.
The post-war Soviet Union adopted conventional nomenclature for the government as well as recognizing it was part of a world in which it was no longer isolated.
Pretty much the same reason the Germans changed their anthem in the aftermath of World War II.
Yep, turned out Stalin wasn’t much of an “Internationalist.”