They're a market based mixed economy. Mixed means both socialist and capitalist (public and private ownership of the means of production).
It's Communist in the sense that there's only one political party, the communist party. And their goal is to move towards socialism.
The Đổi Mới economic reforms were initiated by the Communist Party of Vietnam in 1986 during the party's 6th National Congress. These reforms introduced a greater role for market forces for the coordination of economic activity between enterprises and government agencies, and allowed for private ownership of small enterprises and the creation of a stock exchange for both state and non-state enterprises
The economic reforms aimed to restructure the Vietnamese economy away from Soviet-type central planning and towards a market-based mixed economy intended to be a transitional phase in the development of a socialist economy. The goal of this economic system is to improve the productive forces of the economy, developing a firm technical-material base for the foundation of socialism, and to enable Vietnam to better integrate with the world economy.
Hint: communism doesn't work in practice on scales the size of nations. The ideology is too fragile and susceptible to corruption and outside influence and you end up with shit like this.
Before anyone says "it's not real communism" that is the point. It's useless if it's too weak against other ideologies to be properly implemented.
The same argument can be applied for free market capitalism: it's too fragile and susceptible to corruption and outside influence. The reality is that the big economies of the world lie somewhere in the middle.
That's because communism was never supposed to be a thing you just implement and was never meant to exist alongside other ideologies.
Communism as first described by Marx and then later expanded upon by other theorists is merely the inevitable outcome of a global society that has overcome scarcity, moved away from late stage capitalism and values things like workers rights, equality and standards of living.
The biggest divide between communists is usually how we get to that end state. Do you try to ignite a global violent revolution against capitalism, seize the means of production by force and then use dictatorial power to try and force society towards it, like the Soviets did? Or should we make incremental changes over time though existing Democratic channels like democratic socialists? Or do you seize the power for yourself, run the country like a monarchy and claim you've achieved communism?
I am familiar with marxist theory. The problems lie in what you just said. As Marx said, it is the natural progression of a society that has progressed through the stages of capitalism and entered post-scarcity. People who advocate for other channels of achieving communism are misguided, as post scarcity is a pretty hard requirement and a lack of that aspect opens the mechanisms of resource allocation up to exploitation. And unless you can somehow stop shitheads from being born, someone is going to be enough of one to take advantage.
Even the OG natural progression of society version of communism has issues. For one, you still have the shithead human problem. There's always going to be people out there who want it all, and they'll exploit whatever they can to get it. Communism, being stateless, doesn't have particularly good mechanisms for dealing with that.
The entire point of socialism with Chinese characteristics was studying how to achieve post scarcity in a capitalist global economy without losing the leverage necessary for the government to eventually progress towards communism. It's not like this is a unique train of thought.
Marx wrote assuming that revolution would happen in the advanced economies of Germany, France, England, and America. Instead, revolution happened in the agriculturally-dependent economies of Russia, China, and Vietnam.
Socialism works. Workers can democratically direct production at scale. Communism is the goal, but Socialism isn't some sacrifice to get through, it's a marked improvement on Capitalism. Capitalism itself is the sacrifice.
But even if communism was an ideology and an unreachable standard that a community or country was striving to active, you would expect it to be harder to even become a millionaire
Communism is an definitely an ideology. Literally first sentence from Wikipedia: "Communism [...] is a left-wing to far-left sociopolitical, philosophical, and economic ideology..."
But yeah, it's kinda suspicious that every nation scale attempt at communism has ended in failure or a system that is decidedly not communist, whether through internal strife or external influence.