The USD could take a dive against: yuan, eu, gbp, rial, gold, silver, platinum, WTI, SPY, etc.
Only a few of them will matter on a day-to-day basis if you're currently in the US with assets valued in USD.
Couldn't you just exchange your EUR for USD as needed? Use it as your reserve currency?
Couldn't you just exchange your EUR for USD as needed? Use it as your reserve currency?