Here is another example. SAV Goldy hair. Default lighting. I loaded up the hair and then set up my hair shader on the mat zones. First render looks bright and thin. Second render is after I corrected the gamma on the transparency maps to 1.00. You can see that the hair looks fuller but is still glowing. Third image is after checking "cast shadows" in the neck actor. Many, many, many hair models you will buy have shadows unchecked and/or the gamma is wrong on the transmaps and you won't get decent results with any hair shader at that point.

W10, Ryzen 5 1600x, 16Gb,RTX2060Super+GTX980, PP11, 11.3.740