What changes when a 1930 state returns with its population?

What happens if the Soviet Union's 1930 territory, population and infrastructure reappear in the present?

The technological mismatch matters, as does the return of a population with its existing political experiences and leadership.

The premise restores the Soviet Union's 1930 population and infrastructure together. Its equipment and infrastructure would belong to a much earlier period than those around it. A follow-up about removing Stalin introduces a further uncertainty over how other states and the returning population would react. The discussion stresses that the scenario brings back an entire society, including memories of earlier conflicts and grievances. It leaves those reactions speculative rather than resolving them into a definite outcome.