They are losing the ability to raise money through exports (they need that cash), they are having problems getting imported high-end stuff (outside of Iran which that will have to slow down at some point, Iran can’t accept that many IOUs), they are having to bail out large industries (railroad), they are having to import artillery shells which is crazy given that the manufacturing is not close to that of a cruise missile, they are losing air defenses faster than they can make them, their power grid is starting to feel the effects.
And they just burned through 180,000 men over a few months for a town of formerly 60,000 people. That is something they are unequipped to do again, so not the best use of men,
And they can’t just print a shitload of money to try and keep the lights on or the manufacturing going, at least not for the long term.
Are they at the point the Germans were in the fall of 1944? Hard to say, but they are well on the way there. Ukraine doesn’t have to devastate Moscow directly, they just have to make it unlivable for the poors and middle-class by way of fuel and electricity shortages,