They're not going to be caught by surprise.
Distrust of the United States is leading to the eventual rise of alternative global payment systems
Russia and China have agreed to develop shared financial structures to deepen economic ties in a way that will not be affected by pressure of third countries. The move will help both countries reduce the threat of the US government’s long-arm jurisdiction based on the US dollar denominated. SWIFT international payment network.
Both China and Russia have independent settlement programs at various stages of implementation. China launched the Cross-border Interbank Payment System (CIPS) in 2015, an independent clearing system with the RMB as the quote currency. Similarly, Russia has been developing its own financial messaging System for Transfer of Financial Messages (SPFS).
https://www.russia-briefing.com/news/russia-and-china-to-develop-swift-avoiding-international-financial-systems.html/