The US prints two kinds of dollars, the regular kind, then the T-bills.
T-bills get exchanged like dollars, investors/governments buy them because they are thought to be as stable as dollars, but also bear a bit of yield. The US benefits by printing T-bills over dollars because merely by changing the current interest rate, they change the dollar supply. Increasing interest rates lower the value of T-bills, decreasing the supply of dollars (as Silicon Valkey Bank found out...). This allows the US currency to remain very stable.
Referring to the $40T of T-bills merely as "debt" is quite deceptive. It's the global currency. You need enough currency out there to represent the actual amount of wealth, otherwise the values of dollars increases, and deflation is the only thing worse than inflation.
The US' $2T budget deficit is basically the rest of the world paying the US for the privilege of using US currency. The US is printing money, and getting the benefits of spending, because the rest of the world needs dollars to transact. They send us goods, we send them printed dollars. And then we get a president who calls this situation bad, because he doesn't understand what a "trade deficit" is. Utter insanity to have such a position and then just throw it all away.