Soviet Union gets bomb in ‘41, occupies all Germany, France, Italy, Japan

[True Federalist (진정한 연방 주의자)]

Assuming that the Soviet atomic bombs of 1941 are similar to the Fat Man and or Little Boy bombs and that no other changes in available Soviet technology happen, then it wouldn't have the effect envisaged by the OP. Those bombs would be much heavier than the payload capacity of even the Soviet's heaviest WW2 bomber, the Pe-8.

That isn't to say that it wouldn't be useful, but rather than bombing cities, it would be most useful as a way to devastate concentrations of German troops at the front.