Socialism is not an inherently exploitative system, it’s a democratization in the hands of the Workers. Socialism would also not necessitate Imperialism, ie exporting Capital and intentionally underdeveloping countries for cheap foreign labor, which is the modern extreme form of Capitalism.
Policing would be necessary, but rather than existing to maintain classist society, it would exist to maintain classless society.
There’s lots of books on the subject, if you want beginner recommendations I can let you know.