The "value" of money is one of the most elusive subjects most people encounter. The best explanation I have found is that a dollar is always worth a dollar of tax credit to the monopoly issuer, the federal government.

When a government issues currency it uses its authority to levy and collect taxes to drive acceptance of that currency. You can trade seashells for goods and barter other things, but when the tax man shows up you need the unit of account he demands to stay out of jail or to avoid having your property seized.

This causes everyone to be unemployed in terms of the government's currency until they can obtain enough to satisfy their tax obligation. In so doing, it drives resources and labor into the private sector economy priced in the government's unit of account/denomination. Those resources then are available to be purchased by the government without requiring it to have its own revenue source beyond the currency it can create at will.

Money, regardless of being "backed" by a commodity or not, is simply a unit of measure, like inches or pounds. It has no real value beyond its ability to describe other things in terms of price. The price of those things being purchased can float up or down according to their relative scarcity or plenty in relation to the demand for them. The number of the government's units of measure in circulation has no bearing on that. Inflation of a fiat currency isn't a real thing.