All they needed was gullible do-gooders and a absence of resistance.
I am also convinced Putin is an atheist in the finest traditions of KGB.
But I also believe he promotes the Orthodox Church as a repository of Russian culture and the provider of moral legitimacy (within Russia) for his international adventures.
I don't think Putin sees a diffidence between a Muslim, Christian or Hindu. They are just religions to be exploited.
Even Stalin reopened the Churches during WWII, he knew he needed all the help he could get.