If you are interested on contemporary socialist economy professors talking about the experiences in the soviet union and in China, there are some, Richard Wolff is a nice one to start with. He carefully explains concepts of Marxism and to what extent they were applied in various cases, but then focuses on what current socialists advocate for.

If you want working examples of non-capitalist systems, that are sorts of socialist systems, we have worker coops such as the Mondragon coop in Spain, or the Democratic Confederalism of Kurdistan

If you are not interested in learning anything of socialism past what billionaires’ propaganda tells you, you are very free to do so