I think adoption can happen independent of global reserve adoption, and may be the best route. There are some predictions placing the adoption S curve to exponentially grow somewhere between now and 2030 which isn't too far. If this can happen independent of becoming a global reserve currency, then I believe America could transition from dollars to Bitcoin as the main currency of the country in parallel to mass adoption. It would be like two trains running next to each other, except one train track has bad tracks ahead and will derail but you cant stop either train and need to off board passengers to the safe train.

This would be about the smoothest transition I can think of, and while Bitcoin cannot be controlled, world powers could recognize it is the global reserve currency of the world largely dominated by America due to leading the way through mining and sovereign holdings which means America keeps its status as not just A global super power, but THE global super power.

This is also excluding we don't go down the path of CBDC's which while it is not great for privacy, in a lot of ways it would actually still be an improvement over the current fiat system.