There are multiple problems with your analysis.

1) You are comparing theoretical lines of supply from Europe vs actual lines of supply from Russia, China and NK. The problem with NATO continuing to supply Ukraine is that we don't have the shells or the capacity to ramp up production anytime in the next 1-2 years.

2) Russia has its own MASSIVE means of supply (there are 6000+ arms companies in Russia). It is unconfirmed if NK and/or China supplied Russia with shells. Definitely possible and even probable (to my mind). The HUGE difference (in comparison for example to the US forcing SK to supply Ukraine with its reserve of shells), is that Russia alone was producing shells and armament equal to the combined west in 2022. Now Russia alone is producing multiples of the combined West's output.

3) The key difference between the West and Russia, China and NK is that the West has a profit-driven-MIC, and the East has a purpose-driven MIC. The East has kept reserve MI capacity for a long time because they see MI capacity as a state issue, and not a private issue to make profit from the state.

All of the above means that Russia and the East will continue to pull away from the West on production of MI, particularly in Russia. Russia won't need lines of supply from China or NK for anything critical on the front lines, which is in VERY stark contrast to the situation for Ukraine.

Obama laid this out very starkly in 2016 when he presciently stated that Russia will ALWAYS have escalatory dominance over us in Ukraine.