Communism

I was replying in the context of the comment that you were replying to, which I believe to be referencing historical self-professed attempts at socialism, which have ended in various kinds of disasters.

No one here is saying that all AES states aren't actually Socialist, that's something you added. What "various kinds of disasters" are you referring to?

Governments that profess themselves to be socialist have a tendency to centralize almost total control over the laws, courts, and economy in the hands of a very few people. When this happens, it leads to human rights abuses, and other issues. Admittedly, some self-professed socialist countries are doing relatively well on this, but it's by having strong constitutional guarantees of rights, a multi-party democratic political system, robust trade in goods, and limited state control over the means of production, and the economy at large.

You're a bit off there. Central Planning is a core aspect of Marxism, but compared to Capitalism the participation of the Workers is far higher and more democratic. Saying it "leads to human rights abuses and other issues" is just gesturing, you didn't explain how, why, or what here, just a vibe. The state does not need to be limited in control, giving Capitalists control removes worker participation.

This is where I think you're not asking these questions in good faith. Consider a case where a brand new life saving invention is made. If this hypothetical invention took minimal time and resources to make, would it then be extremely low value? By contrast, imagine a new food is invented, which is bland, unappetizing, and even uncomfortable to eat. On top of that, it takes many years of diligent work, and comically large resources to produce. Is this food very valuable?

This is a misunderstanding of what "Value" is for Marxists. Marxists specifically break down Value into Use-Value, ie how useful something is, Exchange-Value, ie its natural price, and more.

The brand new life-saving medicine would be very useful, yes, but what price would it fetch, assuming no IP monopolies? The answer is extremely low, if it took minimal time and resources. This happens in the real world, vaccines are incredibly cheap once developed, it's only in monopolistic markets like the US that this trends against the natural price.

RnD would, of course, be factored into the end Value, as a form of Capital investment. Over time, the portion of RnD "embodied" into new commodities produced goes towards 0, ie if it costs 5000 dollars in RnD and 1 dollar for every vaccine produced, the first vaccine would cost 5001 dollars, but the second? 2500.50, and so on and so forth until it reaches 1 dollar.

To accept the labor theory of value, you must accept both absurdities (and throw out any ordinary connotation of the term "value"), or engage in special pleading to sabotage them.

No, you must understand the LTV.