every communist group has been undermined by the US.

And honestly, thank God for that. US and especially CIA have saved perhaps even millions of lives doing that.

Cuba has done pretty well for itself despite not being able to trade almost at all, for example.

Gotta hand it out to Cubans, credit where credit is due. Also Cubans have only genocided a little, though it is an interesting thought experiment to have if Cuba was situated in-land with considerable minorities.

But then we have countries like N.Korea which actively trade with the world thru china yet are shitholes. Or china itself, which was a such a shithole it legitimately had to abandon every part of the economic-portion of communism (but still of course kept the totalitarianism and genocide intrinsic to communism) to make itself stay afloat.