Like everybody else, Russia has choices.
I can’t see the perpetual solution to Iran being to keep buying it. That gets Russia some time, but Islamic nuts are Islamic nuts. The USA under Trump could give Russia a chance to get off of that growing tiger.
Historically, Russia has a history of conflict with Persia going back many centuries into czarist times.
Russia’s history of conflict with the Turks is every bit as extensive — and better documented in English, if you know where to look.
I’ve been doing a lot of reading lately about World War One in the Middle East. Although I thought I was reasonably up on Gallipoli, Kut, the Arab Revolt, and so on, I was surprised to learn that Russians and Turks fought fiercely in the Caucasus region.
So, if history is any guide, it’s hard to see any lasting rapprochement between Orthodox and Moslem. They are hereditary enemies.