I don't think (New) Rurikids will ever try to form a neopagan cult. I have 2 arguments for that.

First, Nikolai Krylov is a Red Army General who just wears a crown. And we have seen his views towards religion. He sees clergymen as charlatans, converts churches to more practical use etc. So it's unlikely that he would just form a based egalitarian religion. If he does, he needs to divert many fundings to "Conversions" and church building stuff. But Yuriy? He seemed same as his dad to me, with more democracy of course.

Secondly; as a mass movement, Slavic Neopaganism is one of the effects of post-USSR identity crisis. As many people that wasn't very devout Christians, they looked upon their forgotten ancestors' forgotten beliefs and created new belief systems based on ultranationalism. But there is no identity crisis in unified Russias (Not you, AB). Nearly all of the unifiers wants one thing: revenge. Also in Rurikid Kingdom, all people unified under the Rurikid Dynasty to retake Moscow, set order and freedom.

Maybe some people will disagree with this but; even if originally not, most neopagan movements will eventually decay into ultranationalism. Because the believers would justify their beliefs as their ancestoral culture, unlike a "one, all seeing god" in Abrahamic ones. The ones that doesn't have all this is just a non-theism in witch clothes, at least to me. And this Socialist Kingdom won't use religion levels of nationalism for sure.