Russia has to have at least one active ally for this to be a ‘World War’.
Otherwise it’s just going to be forty or so countries allied in the reduction of the Soviet threat.
Yes, world wars are the result of alliances dragging other countries into a war. Russia’s alliances broke down 30 years ago and are in a shambles now, and Ukraine has no real allies of their own to speak of. So unless Russia does something supremely stupid like attacking a NATO country, there’s not going to be any “world war”. Even if Russia did that, I don’t think there’s any guarantee that even China would back them up, since China would probably prioritize their own survival and make decisions accordingly.
Good thing they will meekly accept their defeat and not use any of their "worlds biggest arsenal of nukes" because they're such good moral guys.