The transformation of payment and settlement relations between Russia and China has been studied in the context of sanctions pressure and the desire to reduce dependence on the US dollar. The main focus is on the key challenges analysis: national currency exchange rates volatility, low liquidity of the yuan, and technological vulnerability due to the use of Western payment systems. The prospects of creating a new reserve currency within the framework of the BRICS as a tool for diversifying the global financial architecture have been considered. The methodology includes structural modeling, meta-analysis of academic research, regression analysis of International Monetary Fund data, and predictive modeling. A three-stage model for implementing a new reserve currency has been proposed, from developing a bilateral unit of account (yuan–ruble) to integrating digital currencies (e-CNY, digital ruble) on a blockchain platform. Special emphasis has been placed on technological solutions such as atomic swaps and quantum-resistant cryptography to reduce transaction costs and counter sanctions. Risks have been identified, including macroeconomic imbalances due to China’s dominance in the currency basket and the threat of cyber-attacks. The scientific novelty of the study lies in the synthesis of the currency choice theory, empirical data on Russian-Chinese trade, and long-term forecasts that form the basis for the transition to a polycentric financial system. The practical recommendations are aimed at harmonizing the regulatory framework, expanding the liquidity of the yuan and coordinating the actions of the BRICS countries. The study results demonstrate the new reserve currency potential to strengthen economic sovereignty and reduce geopolitical risks. The study may be useful for regulators, financial institutions, and businesses involved in projects on de-dollarization and cross-border settlement systems development in the context of geopolitical turbulence.