COVID relief funds are only paying them more than their normal wage because they got paid so badly to begin with. All older generations have averages incomes significantly higher than what COVID unemployment pays. And that's despite Millennials being more educated than all of these prior generations.
It's finally given many of them the freedom and agency to choose their jobs rather than take the first thing they can find to avoid going broke. Many of these people looking for jobs were also the first laid off at the beginning of the pandemic. Why should we feel bad for companies that treated these people as disposable?
There's not a "worker shortage". Companies are complaining that they have to raise wages to attract talent because workers are shopping around and getting counter offers.
This is not unprecedented. The same phenomenon happened after the Spanish flu, and was arguably a big factor in the collapse of the fuedal system during the black death.
Wide scale destruction of jobs followed by increased demand gives workers leverage. You have a huge group of people not afraid of being jobless because they already have been.
We have to remember that 600k people are dead too. A decent chunk of available labor is gone forever.
COVID restrictions blocking employers from hiring foreign labor is also a factor. There's increased competition for American workers because it's harder to import cheap labor