There is a body of Russian Orthodox prophetic literature about Mother Russia driving Islam out of Eurasia and reestablishing Orthodoxy in Constantanople and Christianity throughout Europe.
I would not take Putin’s pretentions to Orthodoxy seriously, considering his crimes. The Eurasian “strategists” view religion as, well, the opiate of the masses and a tool they can use towards promoting nationalism. The end goal is a reborn soviet regime, and it is unlikely that religion will survive beyond its usefulness to long term Russian strategy.