IIRC Marxist Paul and Second Thought did two companion videos last summer about just some of the EU's current misdeeds.
The EU uses one sided contracts with north African nations to push the functional EU border south of the Mediterranean and keep migrants away. The countries are given some small amount of development aid, and in return they set up migrant detention centers and militarize their borders to prevent people from moving north. Most of the destabilization of Africa comes from the lasting effects of colonialism. Now France and Spain want to build pipelines to bring gas across the Mediterranean, taking yet more natural energy resources from people who largely live without electricity and clean water.
Of course a lot of cheap EU food and resources come from the global south. Frontex isn't talked about much but it's basically the EU's version of the hyper militarized US border patrol.
The EU was started by and is even today run by people with Nazi connections. In terms of bringing imperialist class relations into Europe, the EU succeeded with the pen where the Nazis failed with the sword. The east and south of Europe are for cheap labour, the core is for the wealthy capitalists and the labour aristocracy. Due to freedom of movement (for capital most importantly) a German or French capitalist can exploit far more Polish or Greek workers than they could their own countryfolk.
The EU itself is a supranational body which can force member states to adopt laws they do not want. The premier EU institutions, the commission and court, are not elected bodies. There were some national referendums on big EU legislation where the people of the countries voted no, we don't want this. The EU forced it through anyway.