most of the time when a local model feels dumb its not the quant, its the chat template. a lot of gguf mints just drop the template from the metadata and the runtime silently falls back to chatml. model still talks fine so nobody notices, it just gets noticeably dumber. got burned by this myself serving qwen, now i grep the gguf for the template tokens before i blame anything else. second place is sampling, people run whatever defaults their ui ships instead of what the vendor recommends and then compare that to benchmark numbers that were run greedy or with the official settings