You just can't seem to comprehend the concept that money isn't wealth, it's only a measurement of wealth.
National debt is an opportunity cost, when the Feds borrow $100 and give it to someone to hire 10 guys to dig a hole, there exist something else that the 10 guys could have done but didn't, the damage is already done at the moment of borrowing, not at the moment of non-repayment.
When you repay the debt, you're repairing the damage already done, if you repay $110 on $100 of debt, it's not the $10 you created, it's the opportunity for 1 extra person to do something else he previous had to spend digging a hole. Conversely not paying the debt doesn't incur any direct harm, because the harm was already done when something else that needs the 10 people to do wasn't done, because they were digging your hole.
That's the nature of US debt, US can't afford infrastructure because the people and resources needs has already been used in something else, paid for by debt. US can't afford to build ships or weapons because the people and resources needed has already been used. When interest payment exceeds defence budget, that's not a statement says US has to find $1 trillion in dollar bills, it's a statement that says the amount of people willing and able to do things has been depleted sufficiently that more and more of society's resources now need to be allocated into repairing damage already done, as opposed to creating new value.
Its Chinese industry that creates value and it's China's acceptance of USD for trade that gives USD value, because China can still use that USD to exchange things of real value from someone else. It's this Chinese wealth creation that's repairing damage already done by American trade debt, but China can't and won't repair any damage already done by mis-allocation of wealth when it comes to American domestic debt.