The alternative is already here which is bitcoin but if not on a critical situation like in that of Russia i think it never worth doing away with, ordinarily sanction can not be placed on any country without being evident by everyone that what it does to deserve sanction really worth it, Russia invassion could have been avoided and all the wasted lives and properties could have been ameliorated through dialogue, the whole world believe and see to what Putin did as unethical and something that has the vote of over 95% of the entire world worth requoned with, i believe we all need the support of the western international swift in one way or the other.
let us not take the scenario of China to be compared with that of Russia, China only sit to build on it own internal systems from within and decided to cut itself from the western and international services but still engage in maintaining a good report with the world at large regardless of any country, meaning that China was not cut off from the western and international services but willingly choose to stay off because it has built it own system good enough for survival, lastly China does not engage in any form of human massacre or it equivalent.
If Russia finally decided by going with the use of bitcoin (crypto) i think it can be pretty good because it is a decentralized system, just that the swift ban may affect some exchanges from operations else bitcoin can still be a rescue alternative.