MMT ia utter garbage. It's wishful thinking rationalized by people looking at the current debt burdens and saying, "If things haven't broken under the current stress, the bifurcation point must be higher, and maybe so high indeed as to not be applicable."
The US is in an extremely privileged position in that it is the world's reserve currency, so most of the ill effects from QE haven't spilled into everyday products. At least until recently.
Mostly it impacted speculative assets such as crypto, equities, and real estate. Now it's starting to hit other sectors, jumpstarted by the supply side constraints introduced in covid.
The US is able to print dollars and exchange them for real goods. No other country can do that. But once foreign countries stop buyung treasuries and start demanding goods for goods instead of devalued dollars for goods, thr US won't have any goods to trade, and the MMG hypothesis will die with instant hyperinflation drovenby extraordinary supply side shocks to the US economy.
