This is the case for most revolutions. They’re invasions otherwise.

> who is supplying them with ammo and fuel on the road to Moscow?

Again, revolutionaries tend to manage this. Often seizing stuff along the way.

Their existing stocks until they capture Russian state stocks on the way (either by force, or by corruption—money works on corrupt quartermasters, and Prigozhin has a lot), or by turning local troops and the supplies they control to the cause.

But, yeah, outside anti-Putin governments aren’t impossible sponsors, especially if he has some early success. Enemy of my enemy can go a long way to making strange bedfellows.