Europeans are easily identified by their genetics. If anything, the Dardanians and Illyrians are the remnants of the ancestor population of the Slavs, people who moved North from the area beginning about 12,000 years ago as the ice receded.
European males fall mainly into three Y-DNA categories: R1a, R1b, and I1. All of these genomic groups can be correlated with the area where they took refuge from the ice, and then where they migrated to as the ice receded.
Note that the Slavs are thought to have descended from the original European inhabitants of the areas later called Dardania and Illyria.
Europe has been European for at least 12,000 years, if not 30 to 50 thousand years.
Having said all that, it is also true that much of the populace of Asia Minor is to some extent related to the people who took refuge in the Ukrainian and Macedonian areas after the last glacial maximum (LGM). Islam didn't exist then; land bridges did; and migration was common. The current populations are a mix, and Islam was brought to many of them.
But that doesn't mean that we walk away and say it's all OK. The fact is, the Turks -- West Asians, but also to some extent related to Southern Europeans -- were converted to a ruthless, cruel "religion". And they are not walking away from the tenets of that religion, they are acting according to its dictates.
That is, for now, the main thing which must be strenuously opposed, even militarily.
NATO is on the wrong side in this war. Unfortunately, the Serbs didn't make themselves any friends with the massacres and the militias. Bad politics on their part.
But compared to the history of the Ottomans - which they all know - it's almost a credible response. Without a doubt, it would happen in the reverse situation, and probably will now that the Albanians are in full control.
The point I was trying to make is that linguistically based on the toponyms, the Slavs cannot lay claim to Kosovo and the surrounding areas until the 7th century AD (okay, really around 550 AD). I’m no expert on the genetics, just the language. The real problem is that we have insufficient historical records to make absolute claims. The history of that area is almost all speculative.