When people say things like the GP, they are talking about German early war tanks, not the late ones.

The problem is that the early WWII arms race was so fast that I don't know how anybody can say with confidence that Germany lost to worse tanks than theirs. By the time the allies got any volume into battle, they also got better designs than their earlier ones.

Depends what type of models you look at. There were many German designs that were much less prone to technical breakdowns due to pragmatic and mission focused design choices e.g. many of the Jagdpanzer ("tank destroyer") class like StuG II and Herzer were produced en masse and was very successful. Also, the Jagdpanther was a strong design.