Presumably a FIRE person would be sitting on assets that act as significant hedges against inflation. It wouldn’t be fun but they’d be in a better position than most.

I would argue that the real nightmare scenario is that the rules of the game or government policy are radically changed by fiat. For example, effectively nationalizing private retirement accounts in some fashion to backstop public pension systems like Social Security (which has been floated in the US at various times). A lot of FIRE plans are predicated on retirement accounts existing in something like their current legal form over the next several decades. I am skeptical.

You can't hedge against inflation if it is caused by a collapse in production of the thing you want to buy. E.g. farm workers start a civil war against land owners (think Zimbabwe) and now there isn't enough food for everyone.

You will do better than people who own nothing but your wealth won't last forever.

Yeah, that's the issue. Hyperinflation usually involves large increases in the prices of basic necessities (food, utilities, gas, physical security, and shelter if you don't own your home) and collapses in the price of financial assets. Except for the most hardcore leanFIRE types who are into subsistence living off the land, that's usually levered the opposite way from most retirees.

Being able to count on your own labor and having skills in industries related to fundamental survival are key in hyperinflationary economies. You can't count on the financial system remaining intact in any usable form. Most FIRE plans are about leaving the labor force to live off of returns of capital, though.

Hyperinflation is a nightmare scenario for everyone.

FIRE presupposes having non-liquid asset base, such as actually owning the place you live in, means of transport and potentially the tools you use, first.