Manolis, my brief formal study of your period was done under Trevor Bryce over 30 years ago, so I am not up to date on current opinions and expertise. I can certainly offer no help from a linguistic or archaeological perspective. I can offer one possible parallel that may be of use as a point of debate.

I have done a lot of reading and research on the medieval Arthurian legends, which span Welsh, English, French and German literature in particular.

Without going into detail, it is largely accepted that there probably was a war leader named Arthur who temporarily held back the Saxon invasion of Britain in the early 6th century AD. We have few written records from the time, and the only one of relevance (a monk named Gildas) appears to deliberately leave Arthur's name out of his account, particularly with regard to a battle later attributed to him. Tales of Arthur and his deeds appear to have been passed down largely through oral tradition by Celtic bards in Wales, Cornwall and later Brittany.

By the time these started to be written down Arthur had already acquired many mythical attributes and associations, including a famous voyage to the Celtic Underworld. And a number of his earliest companions are clearly old Celtic gods.

Much of the Welsh tradition, not just about Arthur, appears to have arisen during a Celtic dark age that followed the fall of most of Celtic Britain to the Saxons. As Rachel Bromwich puts it in her article "Celtic Elements in Arthurian Romance":

"As the Arthurian tradition crystallized in Wales, there is no doubt that the remembered heroes of the lost kingdoms in the 'Old North' formed an significant part ... the cases of Urien Rheged,and his son Owain, together with Gwalchmai and Peredur ... Therheroes from Wales ... such as Caradawg Friechfras, ... and Gereint son of Erbin,

a hero who belonged to Devon and Cornwall ... It was the names of these and other

Brittonic heroes, some of them belonging to quite independent stories, which

became grouped around the central figure of Arthur in Welsh sources,

and which eventually came, with Arthur himself, to form the names of

the leading heroes of continental romance. No doubt some of these names

and stories may have been transferred to the French through oral sources in

Brittany, since the Bretons continued for long to remember the heroes

who were celebrated in Britain itself, even though their own heroes failed to

win any comparable recognition, and made hardly any impact upon the traditions

of Britain as a whole. In the twelfth century it can be accepted that

there was in circulation among all the Brittonic peoples a body of stories,

derived from heroic saga, Celtic and international folk-tale motives and

pan-Celtic mythology, representing a corpus of tradition which was their

common property, and to which all had made a contribution of one kind or

another.

"... The cyclic development of the Arthurian material may be presumed to have taken place in Britain and Brittany by successive stages between the ninth and eleventh

centuries, unaffected by any external influences from the continent of Europe."

Rachel's comment that "the Bretons continued for long to remember the heroes

who were celebrated in Britain itself" is I feel of special relevance. They were looking back, like the Greek bards on whose tales Homer drew, to a time after the fall of their culture from a time of greatness.

Taken as a parallel, your argument for dating the oral heroic songs that underlie Homer's epics, to a post-palatial period makes sense to me.

There exists a monograph; Lev Klejn "Anatomiya Iliady" , year 1990ies? but it is in Russian.

The question is whether the Homeric epics are a benchmark for the earliest time, or not. Because the Homeric epics only are the first ones which were written down when writing came to Greece. Who knows how long this and other (!) epics were performed before? And what existed before the epics? Was there a time of silence when the form of epic was not created, yet? - Another thought: If epics came into being by cultural intercommunication with the "East", then a good point in time would be the Ionian settlement on Anatolian coasts. I hope my questions did help.