Hello. I think it's possible. But you need to do a lot of conditions 1 have a strong motivation 2 constantly communicate with different people on various topics 3 study grammar because the grammar of the Russian language as complex as the grammar of the English language. 4 decide for yourself. What is important for you to communicate in Russian or obtain a certificate of C2

Well, I'm not nearly a pro in English but still can speak it pretty well despite the fact that I have never been in an English-speaking country. So I suppose that the Internet gives you the opportunity to master any language without leaving your flat or a house since you can speak with native speakers on here.

Everything is possible. One my friend got C2 just watching movies in Russian. nowadays it is not necessary to move to Russia in order to learn this language and meet Russian native-speakers, we use skype :D