Here’s the neat part - you won’t have to.
BRICS+ don’t want to trade for Fiat USD anymore (read Putin’s speech from last year where he mentions this), and the United States isn’t going to let Western nations begin denominating trade in anything other than their petrodollars lest they completely come apart at the seams.
Unsure what a BRICS+ currency will look like but it’s likely there is going to be very little trade between these poles once the split forms fully in to a fracture.