> North Korea is in such poor shape that they probably can't maintain much of the equipment
Sadly we know from events in Ukraine that NK artillery works and that they have plenty of it. Yes, it's poor quality, but far from harmless.
Also to be clear: artillery is not exactly rocket science. They idea that NK doesn't have huge stockpiles is ludicrous.
It takes more than stockpiles of shells to be able to use it and maintain offensive positions capable of causing harm. From the reports I have seen NK military in Ukraine has been mostly cannon fodder and they are very untrained. That being said, joining the war effort in Ukraine is likely increasing their readiness.