I think non-imperialism doesn't necessarily mean production autarky, that's more of a mercantilist/localist perspective, which isn't necessary for a Marxist economy to flourish.

Trade can, and I could argue should exist between socialist projects, in order to make the working class conditions better everywhere in the world. The biggest question there, is how to do trade differently than the way it's been for the past 300 years, that is, how it can be set up such that it's not an unequal exchange of material and embodied labor.

And most importantly (to me), how does this kind of trade it not perpetuate colonialist tendencies that even other AES states have demonstrated in the past, taking local communities' free and informed consent seriously, even if we "need" the resources in their land, as is the case with many indigenous peoples and small communities, and renewables.