Foreign ministers from BRICS (Brazil, Russia, India, China, and South Africa) met to discuss expanding the Global South-led bloc and creating a new global reserve currency to challenge the US dollar.
Together, the five BRICS members represent more than 40% of the global population, and their share of the world economy (when measured in purchasing power parity) is larger than that of the G7.
And both Brazil and India like to play both sides when it involves the west - or as they would say, they like to be non-aligned which is functionally the same thing.
You may be thinking Brasil under Bolsonaro and Brasil under Lula are the same thing, look at the news since Lula came to power. Bolsonaro is the one who did the kind of stuff you mentioned because he saw the West is crumbling and stayed at whichever side it was more beneficial for him, but Lula is other story.
They aren't, it's just a reserve currency, just like the EU has the euro but uses the dollar as their primary reserve currency, or maybe a country with monetary sovrainty like japan etc is a better example, this brics currency is just a reserve one
Except that's not the framing they view the issue in. They see it as preferable to remaining financially kept on the hook and leash of the US, only to have their chain jerked and be threatened whenever they 'act out of line'.
They can have something like the ECU (the predecessor of the Euro), which was a non-circulating currency. There would still be significant challenges to achieving it but at least it doesn't sound outright impossible.