Modern currency is of course notional, all world currencies now are FIAT currencies ... in effect they are a 'promise to pay' which is backed up by the word of the issuing authority, not as it was in the past, being representative of gold stocks held. The 'Gold Standard' was dropped because it held back trade.
The more currency that is printed, the less each unit is individually worth. Because the issuing authority most often, such as at present with the US, has not increased output, it is merely creating greater money flow.
This process can lead to Hyper Inflation, essentially where the value of the currency plummets, inflation is in Millions/Billions/Trillions of % a year not the 3, 4 or even 8%.
I'd suggest you read up about Germany 1921-1924 and Argentina in the late 1990's early 2000's to see the effects of that. Hyper Inflation does not happen by accident, it is a mechanism used by the establishment to kill off debt at the expense of the masses, their life style and their savings/pensions. It is clearly created, it is not an 'accident'.
The US has an extremely over inflated (sic) view of itself
and it's currency which all began around 1917 .... The fiscal hegemony which the US enjoyed from around 1918 to the early 2000's is gone ... It started to sag in the 19070's but was finally made dead and buried by the 2008 collapse.
Whilst many 3rd world countries do use the $US as their black market currency that is now historical in nature. However since the Renminbi has become fully tradeable and of course there is the €uro, the $US has lost much fiscal power just as the US has lost comparable trade.
As a headline for the masses and example the US is 'fighting China' ... The reality check is that China already owns much of the US fiscal system and not a little of the actual land mass.
The basic bottom line is if a country expands it's money flow to reflect an increase in productivity, then it is all good ....... If it is as an initial step to momentarily quell inflationary pressures, it soon creates a situation where a lack of confidence in the currency and surrounding economy triggers severe inflationary pressures.
Too many people in the USA seem unable to grasp that the USA is now a post industrial entity ... It used to import vast amounts of raw materials and then sell that out as vast levels of finished manufactured goods.
Now it exports raw materials and buys in finished goods ... This is where all the unemployment, drug abuse, crime in general and so many other negative social traits began and are multiplying for the USA.
America, just like the UK which is also post industrial, cannot be made 'great again' because manufacturing is no longer as it was 50 years ago and within the next 50 years it is estimated that 80% of all present manual labour/service industry/manufacturing tasks of today's economy, will be wholly completed by Ai and AGi (Artificial General intelligence).
The future for the masses is therefore one of UBI (Universal Basic Income) which is a non-means tested wage replacement benefit to all adults, working or not. This of course opens a vast can of worms starting with "If these people do not produce and are economically inactive; why do we need them? Why are they breeding?"
If yourself or anyone is actually interested ... Then you would need to read many books regarding economics, sociology and psychology. It is all in there. The next century is going to be extremely tough for the masses, country immaterial.