That is a non-expert opinion of course, as more and more countries in Europe submit to gas for rubles scheme, and ruble is now trading above 7 year average to Euro.
Do you know that a cruise missile costs the Russian military $187k? How much Javelin costs NATO?
About 2 weeks ago, I observed a retired Russian aircraft mechanic talking about the changes in Russian education in the 1990s. Funding for apprentice programs collapsed. People asked why and the typical response was that they were going to buy western equipment, which was more dependable and bring in those technicians for maintenance. So as each Russian aircraft mechanic went into retirement....fewer existed.
Look around at Russian military hardware....lot of this is contracted out to Belarus companies now (no longer manufactured in Russia).
FYI, up to the end of December....a fair amount of the parts for the Russian cruise missiles....came from Ukrainian companies. Same issue for engines for the helicopters and fighters. Did Putin or his generals grasp that? I doubt it. The parts depot for the Army is probably shaking their heads over an extended war, and how they won’t be able to sustain the requirements.