The COVID relief bills were actually a one-time exception to a 100 year old reality.
1) Congress directly modified the Federal Reserve's charter to give money directly to private persons.
2) There were also payments directly from the US Treasury.
3) There were also things that involved that traditional convoluted process of the Treasury selling more bonds to the international market and pretending not to know that the Federal Reserve is the biggest buyer showing up.
In this case, because of 1), we really did create several trillion out of thin air, from the Federal Reserve itself. Basically Congress always could, but didn't. Easiest way to accumulate dollars is to scare people into believing dollars won't be relevant.
Although the US otherwise doesn't simply dilute the money supply with direct issuances for nothing, opting to primarily create dollars in exchange for corporate bonds and treasuries, there is a market tolerance and demand enough for dollars to support a much greater level of it. Disclaimer: I'm not advocating for anything.