As I understand it, one of the chief German issues was that they struggled to standardise their kit. They had a bewildering array of vehicles and weapons, none of it compatible, all requiring their own logistics train. A lot of their gear was captured enemy stuff too, which made things even worse. For instance in artillery one quote I came across said :
Different sizes of heavy artillery for the same role such as the 149mm, 150mm, 152mm, 155mm... heavier guns in 170mm, 203mm, 210mm, 220mm, 240mm from at least 4 different nations. For light artillery they had the 75mm (German, French, Italian, Dutch), 76.2mm (Russian), 76.5mm (Czech), 100mm (Czech), 105mm (German, French) for well over a dozen different types of guns from different nations.
The "standard" German medium mortar was 81mm but in reality they had to put scores of 82mm mortars in service they took from Russia. They also had 45mm (Italian), 50mm (Russian and German), 81mm (French/German), 82mm, 107mm (Russian), 120mm (Russian/French) mortars from different nations.
You can imagine the truly horrible logistics issues that kind of thing must have created.
Give a man a fire, and you keep him warm for a day. SET a man on fire, and you will keep him warm for the rest of his life...