We’re coming to find out that in the world we’re moving into (declining demographics, multipolar geopolitical landscape, etc) having the reserve currency proves to be more of a burden than a benefit. It’s easy to run financial deficits when the rest of the world is dependent on your money to trade and store value. In a multipolar world, sustained trade deficits makes you the dependent.
The United States will at some point lose reserve currency status but will retain military and economic dominance by virtue of having the most productive economy, and the largest combined resources of gold, fossil fuels, bitcoin, semiconductor manufacturing, etc.