Artillery Production Incentives (Ukraine, Russia, Every Country that Borders Russia, Why would China want to supply Artillery Ammunition to Russia logic path

Greetings Friends, I've been watching a decent amount of Perun videos of late which are mostly focused on logistics vis-a-vis modern militaries and the War in Ukraine especially; but in this video https://www.youtube.com/watch?v=1zcUe47xerQ toward the end he seems to have meandered, briefly, into an interesting point; what is the logical incentive for China to supply Russia with ammunition; is it to ensure Russia doesn't fail or succeeds or to have any direct impact on the war (unlikely) or is it to build up and sustain their own industrial production of ammunition for future conflicts. This is most assuredly going to happen in every country that has an eastern border with Russia or Belarus (So Finland, Poland, the Baltic States etc.); but China itself may simply want more ammunition even of shorter distance variety at some point in the future. So by supplying Russia with ammunition now they are developing engineers and factories for future wartime production; thus pre-emptively taking advantage of a "War Boom" production model. All of that being said everything points to stalemate in Ukraine aside from potential Russian Civil War randomly negating that which went back to being kind of unlikely but hard/impossible to tell.