Germany would win hands down. The KPA at the peak of its power (as in during the early period of Korea War) bare had any tanks, and what little they had are the T-34 given by the Soviet.



Germany on the other hands can roll out hundread of armour every months, including the newer Panther, and Tiger which are much more advanced than the armour forces that the KPA had (not to mention the fact that they can replace any losses so long as the crew survived while the KPA tanks would be lost forever without involving the Soviet in the picture).



Germany also had almost 4 million troops at the peak of its power while KPA bare had around 200k and even if you take all the Chinese Volunteer Forces into account they would still had rougly over a million, poorly trained troop while the Wehmacht was among the best army in the world. They do also had much larger population which would allow for an even larger reserve against the the KPA.



Depending on your definitio of Korea forces, if you counted the Soviet air support which does not belong to or locate within the Korea boundary, the KPA will likely have air supriority due the availability of jet figther at their disposal. While the German do had jet too, they are not part of the Wehmacht at the height of power and also of much older design and few in number.



However, the German did beat the Soviet Red Army, the role model of the KPA without air supriority numerous times and sometime the Red Army need up to 10:1 ratio to defeat the German forces (Battle of Seelow for example), I think they will have no problem chewing the KPA who only had one third of their strength at most.