That's a good question, for which I don't really have an answer.
After thinking and writing what is below, I think the electricity is the answer. That seems like the one thing that affects both the war effort and the social elites. China, North Korea and Iran aren't sending any extra electric power to Russia.
The main value of Russian Oil & Gas is export value, the cash and currency that drives their economy. Yes, they need the refineries and finished products, but having money always works, especially when you don't make and sell anything else. They can always buy gasoline and diesel if they have money.
Queue Willie,
"Turn out the lights
The party's over
They say that all
Good things must end..."
My reasoning for the above.
Does Russia lose the war because of socialites in Moscow and St. Petersburg are upset, or because the conscripts & criminals on the front limes don't have food, fuel or ammunition? Common sense would say the war effort, but I don't think that is right.
Russia has ~ 25 refineries over a 100,000 bbl/day capacity, all of which have been hit repeatedly, other than the 3 located in far eastern Russia. Extrapolating Ukraine's success the past 2-3 months for another 3-6 months would seem to be enough to deprive Russia of transportation fuel in a meaningful way, which means some things quit moving.
Taking what I know of the US, and applying it to Russia is folly. The US is all about supply & logistics, and that isn't Russia. The US energy infrastructure is much different than Russia. Our nationwide distribution system is much more pipeline oriented and very little rail. Capitalism, and a free market system with profit opportunity drives a lot of private investment, which means infrastructure anywhere and everywhere. Soviet Russia seemed to be a giant support system for Moscow, with everybody else getting the bare minimum of support and infrastructure. One thing I've notice is most of the energy infrastructure buildings have blue roofs. I assume everything that is blue that isnt energy related is from the graft and corruption in Russia.
Google tells me Russian rail is dependent primarily on electricity. Electrified rail moves the food and the oil products. Ukraine has increased strikes on electrical substations, and to a lesser degree power generation plants. It seems the targeting those type facilities has been more discreet and not the wholesale destruction of the power grid, for many reasons.
Fuck 'em!!!
Deprive the Russian urbanites of electricity, warm food and light, and bring the effects of war to their day to day lives.