“it sold treasury bonds to raise the money. Now they literally just create the digits on a computer “
That’s silly. Whether the bond gets printed on a piece of paper or it is just a digital copy, makes no difference. Those bonds still have to be sold at a Treasury auction. Does any one who buys stocks today actually request the paper stock certificates? 99.99999% don’t.
Along with that piece of paper is a promissory not to pay it back with interest and often other countries purchased those notes. Had you not heard that China was the largest holder of US debt. When they monetized the deficit, they skipped the sale of the treasury notes and just printed more money.