40%+ internal russian card payments are via their domestic "Mir" system, that is also available in a dozen or so foreign countries: https://en.wikipedia.org/wiki/Mir_(payment_system)
MIR cards are often also co-branded with China's UnionPay, and UP is available everywhere Chinese tourists/business people travel, which is pretty much anywhere relevant enough.
If you want to travel to Russia, you just need to bring with you a UnionPay card, they are just as widely accepted as Visa in Russia, apparently.
I'm not sure what exactly this ban was even supposed to accomplish. Punish Russian citizens, who according to the West, don't even have free elections and therefore had no input whatsoever in this? Seems like an excellent way to win hearts and minds, I'm sure. /s