App Store is unavailable in Russia

What message are you seeing to make you think it is not available? Typically if there is a widespread outage we will see dozens of posts. Right now I am only seeing yours, which suggests it is something specific to your account, equipment or connection.

Here are a variety of resources helping with connectivity issues:

Restart your equipment and/or sign out and back in again, and try again. When using a computer you can also try safe mode —> https://support.apple.com/guide/mac-help/start-up-your-mac-in-safe-mode-mh21245/12.0/mac/12.0

Choose your macOS version at the top.

If you can't connect to the App Store, iTunes Store, or other Apple services, read this support article --> https://support.apple.com/108093

Here's a related article about what to do if you can't connect or sign in to iCloud --> https://support.apple.com/HT203512

If your iPhone or iPad won’t connect to a Wi-Fi network, or if you have related connectivity issues, read this support article --> https://support.apple.com/HT204051

Try resetting only network settings (again, be careful what you reset here!):

https://support.apple.com/guide/iphone/reset-iphone-settings-iphea1c2fe48/ios

Here's a case where using a VPN prevented sign-in --> https://discussions.apple.com/thread/254836813?answerId=259008052022#259008052022

Remove the VPN entirely, don't just turn off.

If none of the resources provide a solution, contact Apple for assistance:

For support, click here --> https://support.apple.com/choose-country-region Select your country, then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.

or:

Contact Apple for support and service --> "See a list of Apple phone numbers around the world."

Click here --> https://support.apple.com/HT201232