On the other hand Russia has had to use thousands of shells shipped in from North Korea.Depends on where you are looking for data. Russia can quickly make shells and weapons that are simple and perfect for this situation if one doesn't care about casualties.
NATO isn't set up that way. Army ammunition factories like the one in SE Iowa are ramping up. One has to remember that the Russian economy is 1/3 gas/oil and 1/5 military weapons pre war.
Also in the equation is Ukraine's GDP is about 5k per year and Russia's is 17k per year with 100 million more people. It's going to be a race, but the reports I get out of Ukraine aren't looking good. One can't just watch videos of all things Russian blowing up.
In the end, one side will break like in WW1. If it's the Russian's then the nuclear option is a possibility