WI/ Skanderbeg joins Hunyadi at Varna or at the second battle of kosovo

like the tittle says what if Skanderbeg joined Hunyadi at the battle of varna or second kosovo have changed the outcome i personally think so since Skanderbeg knew so much on how the ottomans fough and was nothing short of a genius
what if they do win how much do they gain against the ottomans
and if pope pius II due to butterfiles survives and launches his crusade and Hunyadi do to again buterfiles survives past 1456 what effects does it have against the ottoman empire?
 
According to wiki, the defeat at Varna 'allowed the fall of Constantinople', and a surviving Constantinople is a big butterfly. Worst case for the Turks they lose the Sultan, and his heir, and their field army. If they'd gone with a wagon fort and a new good field commander they might have won.
 
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