Who or what decides that your fiat is now less valuable against BTC, gold, and other currencies? Who keeps track of it? The same institutions doing the printing?
You will need to take an economic course to clear your mind and questions on it.
Nothing decides a fiat currency now has less equivalent value than Bitcoin or gold or because of Bitcoin or gold. If a fiat currency loses its purchasing power, the exchange rate of it to another fiat or to Bitcoin or to gold, will become less. Different countries, different economies and inflation rates, different purchasing power for their fiat currencies.
Why would anything they say be trustworthy?
You don't need to rely on any report and can simply go to the super market, use your money to purchase something, and compare what you can buy with same $100 with what you could like 4 to 5 years ago, before Covid-19 pandemic.