Paying for things in Russia

Hi everyone,

My girlfriend and I are planning a trip this February to St. Petersburg and Syktyvkar. I've picked up our Russian visas and now we need to find a way to pay for things in Russia. We're from the USA and so our credit/debit cards won't work (as far as I know). I would really appreciate some suggestions that avoid me having to carry a lot of cash around! Below is some more background info and routes we've already attempted.

We looked into opening a UnionPay card, but the as far as I can tell, the only issuer of UnionPay cards in the USA, ICBC, has blocked transactions in Russia as well.

I have several bank cards from Georgia, but they use Amex and MasterCard, and I haven't had success adding them to services like YandexPay.

Trying to sign up for a Russian bank card online via YandexPay or SberBank requires a Russian phone number. I have no idea where to get a functional Russian SIM card while in the USA. There are listings for some for very cheap on Ebay and AliExpress, but I worry these might be scams.

I would really like to have a bank card that'll function in Russia in advance of us entering the country. But I'm learning it might not be that simple.

Thanks for your help guys!