What if John Hunyadi was less successful in mounting resistance in Belgrade (known to the hungarians as Nandofehervar) against the ottomans in 1456, leading to an Ottoman turkish capture of the city? IOTL, the failure of the Ottomans in capturing the city allowed Hungary to bounce back and annex Bosnia and Serbia while puppetizing Wallachia and Moldova, and the kingdom was briefly a strong regional power under the rule of John's son, Matthias. Unfortunately, Matthias couldn't secure the throne for his sole bastard son and had an incompetent successor who neglected the security of the country, until Hungary as an independent kingdom was defeated at the Battle of Mohacs in 1526.
Suppose that Belgrade falls in 1456. Could this lead to Mehmed II Fatih capturing Budapest next? Would he make Hungary a vassal, or would Ladislaus, The Posthumous, refuse to comply?
Does this cause a domino effect across the Balkans, making Wallachia and Moldavia fall to the Ottoman yoke earlier than IOTL?