Here another opinion about Early Iron age grooved ware and Mushki. She is sceptic that Mita of Mushki attested in Assyrian texts is really the Phrygian Midas.
Uwe Muller discuss various aspects of archaeology in Iron Age Anatolia. She is generally supportive that grooved ware came to Isuwa Melid regions from East, but not South Caucasus.
PS I don't have a definitive opinion on this subject. I have no single doubt that Mushki attested at 12th century BC were from North Armenia. But the later ~700bc Mita of Mushki could be the Phrygia. This kind of things occur when a name is transferred from one ethnicity to another.