Inflation erased U.S. income gains last year

No.

To me the answer is very simple, the primary (not sole) driver is govt printing currency indiscriminately.

It's more complicated than that (lending also increases the money supply) though you're right that "printing money" loosely speaking is the primary irreversible driver.

Of course the printed money has to be put into circulation ( either lending or spending by the gov)

We've had a dozen instances of massive money printing since the 80s but no significant inflation until we had the COVID supply side shock. Now we're getting inflation because of tariff uncertainty, also a supply side shock.

Friedman is wrong, inflation is primarily caused by supply side shocks.

Depends on the default rate, and I'm pretty sure the past year in the US, default created more money than what was printed (even taking QE into account).

Basically why everybody decided to go with money printing during COVID btw, people realised in 2008 that a 2B default is the equivalent to printing 2B, so if that's the case, why not print money instead (that's a bad calculation imho, in my opinion in a capitalist market economy you need defaults for the market to work, and I would say, you need defaults that pierce the corporate veil).

In modern economies, banks create money by originating loans. The government controls this process with various policy levers.

what do you mean by "supply side shock"?

lending increases the money supply and amortizing and default decrease.