Thrace is bordering Anatolia. There could have been constant migration from Anatolia into Thrace. Resulting to Mycenaean-like Thracians. Proto-Greek speakers however could have entered through the Adriatic route, resulting to more Steppe admixture (Logkas) in certain parts of Greece.
We can't ignore a certain degree of Slavic and Vlach admixture into Greece. So there is little need to make a case that Classical Greeks as a whole were 25% (or more) Steppe admixed. However, the Dorian migration could have been another layer of 15-25% Steppe admixed people, mixing with 10-15% Steppe admixed Mycenaeans. Slightly elevating the levels of Steppe of the Classical Greeks. The medieval migrations did the rest raising the steppe admixture to the 25-30% levels of modern Greeks. That being said, the Dorians, although not high in steppe, could have also carried other haplogroups into Greece. Like more E-V13. The classical Greeks will still plot close to Mycenaean Greeks, because our calculators can not easily distinguish between Mycenaeans and Dorians. As for Mycenaean-like Ancient Macedonians in earlier reseaches. That's to be expected. Becuase the Dorian (probably Logkas-like) Macedonians also intermixed with Mycenaeans in the Iron Age as well as Ionian colonists and Thracians alike. They were probably just a bit more steppe admixed than Mycenaenas. Ofcourse this is just a hypothesis. We will need samples from Northern Greece to see if the higher levels of steppe admixture survived well into the Iron Age.
As for Achilles being blonde. Obvisouly I didn't mean Swedish blonde. But rather a rate of blondism which can be described as brown haired by many Europeans today. Enough difference compared to the majority of Mycenaean Greeks for Homer to distinguish him in such a way.
I'm sorry, but this is all conjecture, without any facts to back it up, and the conjecture depends on scenarios which aren't, imo, very plausible.
I have no idea, for example, why Greek speakers, coming from the steppe, probably Catacomb Culture, would have gone all the way to the Adriatic to enter Greece, instead of taking the most direct route in the east and then diffusing from there.
Regardless, as I tried to explain in my response to Leopoldo, the lessening effect of steppe admixture with distance and density of population is evident throughout the Bronze Age. The areas with the most steppe are the areas in Northeastern Europe which were extremely sparsely populated, and in which the steppe admixed people were the first inhabitants or the largest share of the inhabitants by far. The areas with the next highest amount of steppe were Central Europe and Britain, where the Neolithic farmers experienced population crashes as the result of failing crops and pestilence like the plague.
Things were different in southern Europe, including Greece. We can see that, for example, in the composition of people like the Etruscans and the Latins, who were nowhere near the 50% steppe of Central European cultures of the time. It has been said, in fact, that the Etruscans, who even adopted the language of the locals, were the last flowering of Neolithic Europe, a statement with which I happen to agree.
Even in Central Europe, however, there is, after the initial impact of the arrival of Corded Ware people, a "resurgence", if you will, of Neolithic ancestry. The same thing happened with WHG ancestry after the arrival of the Neolithic farmers. In the wake of the first impact, the prior inhabitants aren't going to be buried in permanent, cared for tombs which we can conveniently find. It's only with the passage of time and the incorporation of these prior inhabitants that signs of them emerge.
That is why, imo, we suddenly have these Mycenaean "like" Iron Age Thracians. Now, could some of that ancestry have come from Anatolia? It's possible, I suppose, but it was my impression that the gene flow and culture went in the other direction. If you are aware of archaeology papers which show gene flow from Anatolia during the important period before the Iron Age I'd be very interested in seeing them. However, even if that were the case, by the late Bronze Age Anatolians had increased CHG/IRAN NEO, so I don't see how that would produce Thracians who were Mycenaean like and "lite", because they had a bit more steppe.
As to the genetic profile of the Classical Era Greeks I will wait until we have some more samples to look at. Certainly, the Empuries sample and the Athens one still seem very Mycenaean like. Likewise, the leak from the paper on Campania in the Greek Era talks about a profile with substantial CHG/Iran Neo, so I guess I'm a bit skeptical that the Classical Era people were all that different from the samples we have, but of course I'll bow to the ancient dna when we get it.
Whether there was a "Dorian" invasion or not is hotly debated by archaeologists, and we have no "Dorian" genome for comparison, so anything we say is sheer guesswork. Also, even if there were such an invasion, the likelihood is that they were Greek speakers from more northern areas in Greece so I don't see how they could have made Classical Era Greeks all that much more "steppe" like.