The major difference North Korea made was in two things, the construction of general defensive lines which from the little I know North Korean troops tend to be quite competent at, and in providing an attempted replacement artillery backbone to russia because Ukraine had already irrevocably broken russia’s. I wouldn’t be surprised if a significant amount of russian artillery personnel now fighting on the frontline weren’t actually trained from russians but from North Korean institutional knowledge given how severely and completely the russian military has burned through its institutional knowledge from everybody being killed in the maw.

None of that changes the fact that North Korea infantry, artillery and mechanized elements have no relevance on a modern battlefield in terms of learning how to fight with more advanced tools and tactics. North Korea knows how to pile on artillery and how to build good defensive emplacements, they do not know how to do mechanized maneuver against a near-peer foe using cutting edge technology and tactics, they are not a military well practiced at integrating Close Air Support and Recon elements with other elements in a killchain and most of the equipment they brought was existentially vulnerable to light drone attack (such as the obsolete Koksan and the extremely exposed North Korean MLRS systems that are featured in many videos being detonated by Ukrainian drones.)

I am sorry but russia has achieved nothing of significance since last October? They eventually took Pokrovosk but at the cost russia has paid and russia increasingly continues to pay every day this war goes on, the war is already over. The backbone of russia has been broken, North Korea could not make up for it though they honestly tried. The war will rage on for some time but there is simply no way russia can win it now and every single person condemned to death by russia continuing to refuse to admit it has already lost will be looked back on as a pointless, futile tossing away of human life.