This conversation pretty much says what you need to know. I am surprised to hear about this wet dog smell from merino. I’ve bought KUIU merino going back 5-6 years and I never have any odor of any kind from them. I hunt warm and hot weather in merino and only wash them every 3-4 wears. Even soaked with sweat I never smell anything. But synthetics stink up almost immediately on me. No lie about the Peloton 97. That stuff is incredibly warm for the weight.
I think wet-wool-smell is real, but it’s maybe not so much noticeable in thin fabrics like some base layers. And it’s not an armpit stench. Alpaca has a similar odor when wetted out, in my experience. It’s probably inherent to animal fibers.
With a wet wool hunting coat and bibs/pants, it’s noticeable. Sweaty wool dress suit…no doubt it’s there..
Polygiene treated synthetics suppress oder adequately for me for a day or two even when sweat through, but they are not my choice for warm weather.
I think Jason has it right.