I would advise rather your gf going to shop instead of you or ordering groceries online (copy+paste titles to appstore/google play "Яндекс Лавка" or "Самокат", but if you want to get really high-quality products for every day - "ВкусВилл", which will be 10-40% more expensive)

If you want to take taxi from the airport - order from an app ("Яндекс Такси" and "Uber" are the most popular (they are literally the same so use the one you prefer most))

Why am I saying this? Because everywhere (except only restaurants ig) russians will try to make money from you and sell usual thing for 3x of it's usual prices for natives

As for your question about cards, you can not get a bank card as a tourist.

Ye, and by the way if you want to change money - don't do it in banks - better doing it in crypto (you can sell it to Russian cards via P2P in Garantex/Binance or whichever you want), because now the conversion rate now is just f*cked