Dorico 3 Elements doesn't recognize Kontakt 5 or 6

I don’t know if this relevant but the second picture in your post shows the new path for Kontakt as:

C:/Program Files/Native Instruments/VSTPlugins 64 bit

instead of:

C:\Program Files\Native Instruments\VSTPlugins 64 bit

Forward slashes are illegal in path names if you use Windows, unless Dorico automagically corrects the “/” to "".

Just a thought.