The goal of BRICS is not to defeat the US and become the new world ruler, their goal is to reduce dependence on the USD. Creating a multipolar world with evenly distributed power to make the world more equal, a world not bound or oppressed by a single power. So the scenario of them turning their backs on each other and falling apart is very unlikely, they need to maintain that to keep the world multipolar and that is their goal. How can they easily give up the achievements they have worked so hard to achieve if they succeed in creating a multipolar world?
That has always been the plan. To dethrone the US as the world's leading superpower. I doubt BRICS will take the US' reign anytime soon. Especially with the EU in play. Constant geopolitical tensions in Europe will only strengthen the EU in the long run. The Ukraine war is only the beginning. Already, EU countries promised to spend 5% of their GDP for defense. Will BRICS stand a chance against the EU's military and economic might? Only time will tell.
At the time of this writing, Russia and China are the only countries capable enough to survive on their own. But I can't say the same about other countries within the bloc (BRICS). We're living in uncertain times, so anything's possible.
The EU has US interests and relies heavily on military technology to strengthen arms trade and increase financial co-operation. The US will not waste time chasing EU countries because they are already developed countries and most of them have close ties with the US government. During the Biden administration, the EU provided them with extensive financial and military assistance due to the Ukraine war but after Donald Trump took office as president they reduced their assistance and are now increasing their assistance again. As a result of this war, a process of geopolitically weakening Russia is underway.
Since Russia and China are members of the BRICS, it has become very challenging for the US to maintain the dominance of the dollar and if more countries join this alliance, the US's sole dominance in the world will be reduced and the dollar will fall.