Several 'inaccuracies' in your post. 😁
There are not 7b people in BRICS+.
There is no BRICS economic union, not even a trade deal.
BRICS countries are not particularly known for respecting international laws backed by the U.N., and in particular Russia and China.
In addition, while it is obvious that a more multipolar world will emerge some day, I doubt it will be better. I doubt that being dominated by China, Russia or India will be better for smaller countries, than being dominated by the U.S.