my girlfriend says i grew more hair since i started using a chicken lamp sauna (around 1000 watts total)

There are many reasons to doubt the conclusions reached by those studies.

One of which is: Most observational diet studies use derived variables such as sfa pufa in the diet. But they derive those variables from questionnaires, with questions such as how often did you eat cheese or butter or margarine. Then they use some formula to convert that into amount of sfa or pufa. This can create a lot of noise within that data. Many people don't know the difference between butter and margarine (so someone can be guzzling on pufa margarine but in the dataset is now in the high sfa category.

Foods that regular people eat also change in time. The first study you mentioned started in the 1980s, when the same food could have different nutrients, such as additives, pufas etc.

Pufa intake can then load onto different foods, eg if there wasnt pufa added to everything, then pufa intake would just be a proxy of eating fish, nuts, seeds and vegetables. And not soybean oil. Those products are also often proxies of wealth and status. I also wonder what the people in those studies eat if they fall into the high sfa category without being a peatard, just deep fried lard or partially hydrogenated soybean oil? Being in such a category probably also correlates with other variables that correlate with bad outcomes.

If you look at studies that correlate individual foods with certain outcomes (e.g. butter vs mortality, cheese vs mortality), the effects are often null or suggesting benefit. Such studies are much closer to the real world, because people eat foods not sfa/pufa/etc.

And then there are also animal studies, etc.