Countries are already moving towards bilateral currency swap agreements where possible, and some regional blocs are proposing multi-currency baskets or a non-aligned unit of account for their settling of accounts. We will see this trend accelerate as more and more countries realize that they are now free to make these agreements with the US no longer able to convincingly enforce its Bretton Woods dollar hegemony across the world.

There are also discussions occurring around a sort of Keyensian Bancor for the 21st century, something that BRICS is positioning itself to be able to facilitate, realistically maybe beginning sometime in the 2030s.

There are likely more options being discussed, yet more theorized, and maybe some new ones will be born out of the experience and knowledge gathered in the trial phases of various systems. What I do know is there will not be one single currency taking the place of the US dollar as global reserve currency. Not only is it unsustainable, it's the opposite of conducive to a peaceful and prosperous humanity.