I happen to use Artomatix before they did this shadow removing node. I couldn't say how good it is. but from what i see in this page it looks rather like selecting shadows and then play content aware fill within selection . You could perfectly recreate same process in Photoshop or Affinity Photo. Artomatix looks like doing…
My antivirus says something malicious in your download page. =) For highlights try to use levels with luminosity blending mode + a bit of "blend if" sliders to make the levels not working for darker under layer pixels, for super strong highlights you could also use same content aware fill technique, if you have accurate…