>* Does anyone actually understand how money works, or are people trying to rationalize what we already have?
I would say, no.. considering the divergence of expert opinions. Limited consensus have formed around high profile economists (eg Keynes, Friedman) but generally erodes as history throws up new examples that don't fit neatly into popular theories.
Monetarism is still the working understanding behind most central banking, but japanese staglation and later events (arguably including the current covid economy) have demoted it from "a theory of the truth about money" to "a method of doing central banking."
I do think that since pure fiat currency became the norm in the 70s, our understanding of money has improved. We are forced to conclude that "the truth about money" can only be found in financial systems, because there is nothing else anymore.
It's not really a question academics are trying to answer, atm. One reason is that trying to answer "what is money" is associated with all sorts of ideological quackery with a bad reputation. Another reason is that high prestige economics deals with a more pertinent question: "what should central banks and regulator do."
The economist who answers this question becomes the next JM Keynes or M Friedman. At the least, he becomes a central bank governor. This limits the field of search to stuff a central bank can do. Economic understandings are also generally curbed by what can be measured, and this also limits the field of search.
> * All that really matters (to me) is the value is relatively stable and it doesn't create a crazy imbalance of power.
> * Money does an okay job maintaining a stable value for some stuff (e.g. food), but an incredibly lousy job for other stuff (e.g. land).
These are not universally agreed to be products of monetary systems. Stability is, under the current theories used by central banks (mostly monetarism) but the others are explicitly "out of theory."