Russia’s position on this makes sense on a couple of grounds.
Theologically, it’s a Western Church vs Eastern Church war.
And the Pope is an American leading a body which in recent years has become a liberation theology church.
It could be that the Pope could prove to be an honest mediator, but he doesn’t really have a track record in that area yet, so far as I know.
It’s a holy war?
The other thing that Russia wants is the ability to negotiate with UKRAINE, rather than the Neocons via Ukraine. If in Europe, it will be much easier for the Neocons to direct the negotiation than if in Saudi Arabia, for example, as the Neocons would not be invited.
Of course the Neocons could use phones, but it’s no secret that we tap all important calls.
It isn’t a war between theologians at all.
It is a war of conquest by a Stalinist wanna-be emperor for natural resources and personal wealth, nothing Christian about it.
Religion has nothing to do with this war. The Ukrainians mainly Orthodox.
The Pope is offering a venue, not proposing to mediate.
Stalin was a former Russian Orthodox seminarian. But I think he was less religious by then.