In Yemen, the US-led airstrikes have bombed hospitals, markets, etc. as recently as a couple years ago, leading to the largest humanitarian disaster in the world: https://www.washingtonpost.com/investigations/interactive/20...
In multiple countries across Africa, US-trained officers have led numerous coups: https://theintercept.com/2022/03/09/intercepted-podcast-afri...
Yes, it's true that USA seems to have stopped overthrowing governments in South America (if you don't count the coup in Honduras, or our upcoming invasion of Haiti). But countries across south America remember the decades of overthrowing governments and installing our puppets there. And countries across Africa are seeing it today.
Collectively, the "global south" and the "middle east" doesn't have a great view of the USA. So it's not surprising that many of them are joining BRICS as a way to have some allies against US aggression and hegemony, or at least counter its financial dominance with the dollar, world bank and IMF. It's not unlike the governments of countries that experienced USSR's aggression and hegemony seeking to join NATO, in order to have some allies against USSR, and now against Russia. It's not necessary for all their interests to align, in order for some of them to align. "The enemy of their enemy is their friend", is very much in play here.
But you can go further, beyond governments and politicians (as I like to do) and look at polls of regular people around the world. It's not very favorable to USA. Not just "years ago", but let's just look at the last 20 years. The public in our allied countries in Europe named USA as the greatest threat to world peace:
2002: https://www.pewresearch.org/politics/2003/12/10/anti-america...
2007: https://www.ft.com/content/70046760-27f0-11dc-80da-000b5df10...
Across the rest of the world:
2014: https://nypost.com/2014/01/05/us-is-the-greatest-threat-to-w...
2021: https://www.theguardian.com/world/2021/may/05/us-threat-demo...
2022: https://thewire.in/world/more-indians-hold-us-nato-responsib...
2007: https://www.ft.com/content/70046760-27f0-11dc-80da-000b5df10...
There are plenty of legitimate criticisms of US interventionist foreign policy, but that is largely irrelevant to the global trading system. Money talks, and most of the countries with money (or goods worth trading) are at zero risk of a US invasion.
As for Niger, it's not a member of that bloc nor has it even been invited to join. Regardless of how much uranium they export, they will never have any influence over the international financial and trade settlement system. So, I don't know why you would even bring that up.
BRICS is not about cooperation, but rather about allowing each independent country to fully pursue their own self interest. Right now that's not really possible when relying on economic systems controlled by the US. So we're seeing a gradual shift on the currencies countries hold, US debt holdings, the development of e.g. SWIFT alternatives like SPFS, and so on. The development of a common currency will be the next logical step.
The world order as you know it today is not even remotely "natural." And this is a fundamental component to try to appreciate the geopolitical relations between countries, as well as how other nations are going to perceive the various threats of the world.
[1] - https://en.wikipedia.org/wiki/United_States_involvement_in_r...
[2] - https://worldpopulationreview.com/country-rankings/how-many-...