Bitcoin does not need to be assessed by the USD value. For example, if you look at the hyperinflation in Venezuela compared to the free market Bitcoin value, the hyperinflation is technically more that 17000%.
Once the USD falls, which it will, you will judge prices in Bitcoin based on the denominations of Bitcoin. People once bought products in half cents, cents and nickels. A dollar was a lot to most before inflation truly hit. One can do the same thing with either Bitcoin as a dollar and the smaller denominations which many of us see in our wallets when we buy products or services.

As for whether Bitcoin itself or USD designates the value change, the USD may be devaluing but not enough for Bitcoin to go from $1800 to $4400 in less than a month. In comparison it's minimal. If it devalued that fast it would be one of the most dramatic hyperinflationary events in history. lol