Your "for nothing in return" is actually for the capitalization of the US dollar as the world reserve currency. If you thought price inflation was bad after Trump's last spree of helicopter money, just wait until other countries' USD reserves are being dumped in earnest.
Dump in favor of what? Euros? Yuan? Gold? For better or worse there's still no practical alternative to the dollar as the world reserve currency, regardless of how the supply is inflated. The BRICS group keeps talking about creating a new currency for international trade but they can't agree on anything specific.
The EU seems like a more stable thing than the US these days. Japan has always been a stable thing. The west can’t really do India or China, but those would also make better options than the US right now. It’s not unprecedented for people to flee the USD.
You're missing the point. There's not enough Euro or Yen denominated assets to make that work.
https://www.nber.org/digest/apr20/why-euro-hasnt-become-inte...
Could always move to a basket of currencies, that’s been proposed before
All of the above with some real-time algorithmic settlement wizardry tying them together? Plenty of neoliberal looting to be had on the transition from countries holding high masses of assets to lighter weight just-in-time financial engineering, too.