Basic life skills: there are these things called money markets (think stock market) and money exchanges (think bank with stacks of various currency). Both let you trade currency for currency. The market one is how the news reports the "strength" of one currency against another.
If you believe this invalidates my earlier statement, you fail to understand the basics of currency market operation. Effectively, every currency trader is placing a bet on the future relative demand of two currency vs each other. If they bet correctly, they make a profit ... if not, they lose their shirts.
This market is no different than the futures market for any commodity. Just as oil traders do not manufacture or consume petroleum, currency traders cannot produce dollars or yuan on demand:
the ultimate source of their trades are the monies spent between each nation to buy and sell goods and services. And despite what youi believe, these markets don't exert long-term control over exchange rates. In a hypothetical situation where every single trader wrongly guesses that the dollar will strengthen sharply against the yuan, the dollar will indeed rise briefly -- but when the contracts come due and cannot be fulfilled, all those traders go bankrupt and the exchange market collapses.
There's a term for why this doesn't happen:
convergence. Convergence exerted so much force during the Covid oil supply imbalance, that in April 2020,
oil prices briefly went negative -- traders were essentially forced to pay people to take delivery of free barrels of oil. Weeks earlier, traders had wrongly bet on how much oil would be demanded, and many went bankrupt. Long-term, convergence requires the future price to meet the spot price, and the spot price equalizes instantaneous supply and demand.
At this point, you'll likely protest, 'but exchange rates
affect demand'. True. But if a change in exchange rates isn't driven by underlying factors (the "wrong guess" I mentioned earlier) the demand effect is being subsidized by money from trader's pockets. As in April 2020 when negative oil prices briefly forced the market to buy more than was actually consumed, that was financed through hundreds of billions in market losses-- and the demand imbalance finally corrected by the bankruptcy of more than 100 suppliers.
I recommend Basic Economics by Thomas Sowell. My 12 year old is currently reading through it
As much as I love popular economics authors like Sowell, Hazlitt, Gilder, and others, you really need meatier material to gain a real understanding of markets. Might I suggest the indomitable Milton Friedman, of whom I own many works?