If you think the balkans had no impact to the ottoman empire (and therefore turkish history) you must be blind. The Balkans where much more important than the middle east (economic wise, soldiers wise and also for food), iran was never a part of the ottomans they were enemies most of the time. Without the balkans the ottomans would never have conquered egypt or Instanbul, and 80% of all sultans were South slavic / greek / Albanian. The Ottomans were not a Turkic empire, but a multi ethnic one, there were times when there were more christans in the empire than muslims. So the success of the Ottomans is only partly because of turks, more a combination of all ethnicities. Some small stuff the Ottomans got from the balkans, you can find much much more:

Military & Administrative The devshirme system recruited Balkan Christian boys who became the empire’s most elite soldiers and administrators. Many of the greatest Ottoman grand viziers were of Balkan origin — including the powerful Köprülü family (Albanian/Slavic roots) and Pargalı Ibrahim Pasha (Greek). The Janissary corps, the empire’s premier infantry, was overwhelmingly Balkan in composition for much of its history.

Economic Engine The Balkans were among the most productive agricultural and commercial regions of the empire. Cities like Thessaloniki (Salonica), Sofia, and Sarajevo were major trade hubs connecting Europe to Anatolia. Balkan craftsmen and merchants were disproportionately active in Ottoman commerce.

Architecture & Urban Culture Bosnian, Greek, and Bulgarian craftsmen contributed enormously to Ottoman building traditions. Mimar Sinan, the greatest Ottoman architect (designer of the Süleymaniye and Selimiye mosques), was of Anatolian Greek or Armenian origin — but Balkan artisans built and refined countless imperial projects.

Naval Power Greek and Albanian sailors and commanders were the backbone of the Ottoman navy, particularly in the Aegean and Mediterranean. Hayreddin Barbarossa, the empire’s most famous admiral, was born in Lesbos to a Greek mother.

Cultural & Intellectual Life Greek scholars, Jewish communities (especially after 1492 in Thessaloniki), and Balkan Sufis enriched Ottoman intellectual and religious life significantly.

I would argue without the balkans, the anatolian turks would never have the success they had with the ottoman empire. I like the ottoman empire, and the balkans were next to anatolia the most important part of that empire.