You can sustain a fiat system so long as your nominal tax revenue always grows faster than your nominal debt servicing cost.
If your nominal debt servicing cost is growing faster than your nominal tax revenue then you in a Malthusian catastrophe and your currency will eventually be debased to zero.
We currently have high inflation by design because it reduces the debt/GDP ratio and eases the burden of servicing the debt.
This isn’t an easy thing to do, because it means bondholders are losing purchasing power whilst it goes on. If they sell off it forces you to print more as buyer of last resort and you can actually blow yourself up.
So there’s a fine line, but Fed are trying to walk it. What else are they to do?
Meanwhile, commodities will inflate and you don’t want to be stuck in fiat denominated instruments during these inflationary debt/GDP realignments.