It's all about the hats
After googling, I came to the conclusion that there is no one-size-fits-all solution for all hats and hairstyles. What I found is usually only applicable in that case, but not completely. Although the authors chose the examples themselves. However, these tutorials are only guidelines, but rarely complete solutions. In the end, the only thing that works is the "Geometry Editor" and then after marking the parts of the hair that are excess, you choose "Delete Selected Polygon(s)". To get the best possible result, you need to be quite precise and dedicated to it. In my case it didn't turn out perfectly, but as you can see there are no visible flaws. So I assume that all those promo pictures where the models have a hat or a cap on their head were probably done better than my work, but there were also compromises and improvisation. There are actually hairstyles and hats that were originally made for them. But such are rare, and in one such example that I found, the hairstyle was not really to my taste, especially without a hat.
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