Russian keyboard

You are NOT writing Apple. This is a user to user only forum. Currently, Russian Language is not supported. And we have no inside information on languages Apple may introduce in the future.

Since Apple has exited Russia, one might think it is not a high priority at this time however.

You can provide feedback to Apple via this link --> Feedback - Watch - Apple

Use the link I provided. Enter your name and email address. Choose the WatchOS version on your watch. Choose Feature Request. Enter comments. Hit Submit Feedback.

It will be read, but no one will respond to you.

You're welcome. But again, I wouldn't be holding much hope for this if I were you.