You are totally write. I wrote exactly about that. https://www.lunaroute.com/blog/the-model-is-not-the-product/

We will release our data soon. It's not just quantization, we are using NVFP4 from RadixLabs for GLM 5.3 but with our configuration and the OpenRouter harness for benchmark we are actually #4 in accuracy out of about 30+ providers. We run strictly on Blackwells (B200) on SGLang.

So its not just quantization, its the software, its version, its configuration, the exact hardware etc. They all matter.