In a recent article by Anchor Capital, the fear that the US$ may be replaced as the dominant reserve currency in the world is analyzed in some detail. If you are interested in this topic it will serve you well to read it on their website. Their conclusion is that, although the US$ is currently expensive relative to most if not all currencies, it will be many years if not decades before the US$ loses its dominance.
There is a lot of talk about China becoming the biggest economy in the world and that the Chinese yuan will become the dominant currency, but as things stand now, developing international barriers between the East and the West is of more concern than where the US$ is heading.
As an investor you need not worry about all of that right now. Having a good portion of your wealth in dollar-based assets protects you against the more dire problems in South Africa and the resulting struggling rand. We have to remember that 2024 is an election year in SA and you will hear many more or less crazy stories doing the rounds: do not let them upset you. If you keep your own house clean and do what you can to improve your own community, the rest will take care of itself.
If you look at the graph below you will see that since 2009, after all that we have been through with Covid, conflicts and politics, equities in the USA have delivered a very decent return. It is, however, important to note that not all equities are equal. Something like the management holding company of Warren Buffett is more stable than the technology heavy Nasdaq index, but with less return.