"Ruskie" vs "Rosyjskie" is a difference between common speech and more proper grammar, but in regular usage of the language they both mean the adjective "Russian". I'm native.
I'm an alumni of https://bradfieldcs.com/, and it enabled plenty of us to prepare to work at FAANGs. The courses aren't really for that though, but if you were to take one (I strongly recommend CSI), you will find yourself surrounded by people who crave knowledge and betterment of their craft and are very driven about their careers.
The CSI course itself isn't a FAANG prep nor will you take interviewing or leetcode classes.
Here's a free version (and larger in volume of knowledge) of what CSI offers to enable you to understand and interact with: teachyourselfcs.com/