Welcome to the forum. Feel free to introduce yourself in the Introduce Yourself forum.
My experience with Balkan Sobranie cigarettes dates back to the early and mid 1970s. Yenidje leaf then as now, was not grown in Yenidje (Genice) Greece, but rather, up the valley in area of Xanthi. (Yenidje leaf was famous in the mid 19th century, then the town was obliterated by flooding mid-century. But the fame has lived on.) Yenidje leaf is Xanthi leaf, which is a Basma-type Oriental. There are some seed vendors that sell a uniquely labeled tobacco that they call Yenidje, and some of our forum members are confident that it is different from typical Xanthi-Yaka tobacco.
The closest to commercial "Yenidje" leaf that I've sampled in recent decades is the "Stacked Basma" currently available from Whole Leaf Tobacco:
https://www.wholeleaftobacco.com/product/stacked-basma-whole-leaf-turkish-tobacco/
With regard to vintage tobaccos, my experience has been that tobacco quality peaks at about 10 years, then slowly fades. (It's a race between the volatilization of "detractors" and "enhancers".) Twenty-year-old vintage cigars (properly stored) are still "nice", but nearly always a disappointment.
Bob