Working on Hair is Tough

Do the CS6 Brushes not work in Photoshop 2021? 

I love the tutorials from Photoshop Cafe by Colin Smith. Check them out.

https://photoshopcafe.com/cutting-hair-fur-photoshop-automatically/

https://all-free-download.com/photoshop-brushes/

In my past life as a magazine retoucher I would just use a standard brush with the smudge tool, plus rough feathered selections with motion blur.

That being said, many seem to like the Nagel Hair and Fur Brushes:

https://holeintheplot.com/share/tools/brushes/

https://www.photoshopgurus.com/forum/threads/nagel-brush-series-anyone-have-a-list-of-names.31510/

The Hair & Skin Texture Brushes by Castrochew were my goto brushes for many years.

Skin and Hair Texture Brushes by castrochew on DeviantArt

But the Aaron Blaise brush and texture sets are probably the best you'll find. They are not free, but so cheap they might as well be.  He also does some value for money bundles.

ON SALE! Photoshop Brushes & Texture Sets - The Art of Aaron Blaise (creatureartteacher.com)

It's not hard making your own hair brushes though.  Try single pixel full black with opacity set to fade for flyaway hair.  I usually reduce the layer opacity for best effect.  Always use fully hard brushes on their own layers.

A couple of this forum's regular posters assisted Dave Cross at one of his MAX workshops a few years ago, and he told us a story about masking a lady with flyaway hair.  Scott Kelby and the other Photoshop Guys could not understand how he'd managed to do such an amazing job.  The answer is that he had hand painted fine hair detail to the selected lady.  That's something I have done for as long as I can remember, and it makes all the difference as it sounds like you already know.

Good luck