So we know that the USA can only avoid paying their debt because the USD is the world reserve currency, but once they actually have to pay it, it's going to be hell.
How is China going to deal with their own debt? Because it seems like they have a lot to pay back.
If you ask me- when and as the dollar falls and the US with it, the rest of the world should see to it they get their pound of flesh. One way or another (within reason, but not with any leniency, that's for sure), even if it takes an international coalition or collective effort to do it.
It's not about the "sanctity of debt" (though certainly, there's a strong irony about it considering how the west treats its debtors) but the fact that the US owes the world that much and so, so much more (in reparations)- even just being forced to pay its debt alone would be an utter mercy, generosity even, a generosity that was never offered to the rest of the world, and which would be at the expense of it- and the billions of non-Americans, non-westerners (as someone who lives in the west myself) who live in just as dire and far, far worse conditions due to western design.
Obviously, should conditions get so bad as to be comparable to that of the Weimar republic or even post-WW2 Germany, international intervention and administration will be preferable. But each crime the US empire has committed should come with a price tag, and by all means they should be made to pay it. Same with the rest of the "international community." There are nations that have suffered- that continue to suffer famines due to their machinations. Nations whose land has been completely stolen or destroyed, littered with unexploded ordinance, whose people suffer generational traumas, birth defects, who can point at the west as the ones who incited terrorists or separatists in their land, the ones who bombed their schools, hospitals, public utilities, etc... there are nations who have been very literally enslaved in their entirety, by shackles of debt by the west. It's the west's responsibility to make this right (even if they cannot be counted on to do so) and by all means, the rest of the world, as it increasingly has the means to do so, should and must make it right, even if it takes the imperialist bloc centuries to repay in renegotiated sums, or if it takes the concession of large swathes of western territory to be decolonized (I'd argue that decolonization should be a priority either way- alongside the more important and valid moral reasons of indigenism, the west, and particularly the US/Anglosphere, must never be allowed to reach the inordinate and wholly unearned heights it did again).
The west's stolen wealth, was never its own to begin with. It is for these reasons that it is owed back; because it is not theirs, never was theirs, and there is no place for them to claim that they, no matter how inconvenient the circumstance it might put them in may be (with the caveat being- the basic needs and functioning of society should be seen to as all people have a right to such), have precedence over their victims who are the rightful owners of said wealth- their victims who are the ones who put in the labor, who drew forth from their own nations' resources, etc...
When the time comes due, for instance? All the materiel of the US army should be made forfeit and redistributed amongst its victims (the entire non-western world), what isn't scrap or to be scrapped, anyways. I'd argue there is a strong precedent for the exporting of what machine tools and non-medical, and non-necessary for-the-present-population agricultural equipment and vehicles should be transported, but outside of the US' closest neighboring victims (Latin America) and those decolonized regions within the contingent former US, the logistics as well as practicality of it all wouldn't make much sense- so instead, perhaps what means of production the US presently has and retains should be held on lease to a general trust for those it owes reparations.
Alongside that, there should be a negotiating and dismantling of much of the patents (particularly in regards to pharmaceuticals, but also in regards to technology, etc) held by the US, and a liquidation (where not liberation, in regards to all its various unincorporated territories aka. colonies) of all its overseas assets. There should be actual forced technology transfers as well, between the US and the global south; and there should be a means of strongarming the US and its constituent corporations ("multinational" though they may be) into handing themselves over to international stewardship and management- as non-profits or something of the sort in manners akin to, say, how the various UN agencies operate today.
In all these ways and more, the US should be made to pay- because it must; for the sake of justice (reparations), for the sake of completing the process of decolonization and preventing an imperialist resurgence or unrightful imperialist inheritance, etc.