Teejay
Gone Fishin'
However the Byzantine empire still has control over Anatolia which is a major advantage, before invasion of the Turks. The Byzantine heartland held up against the advance of Islam for four centuries.I mean Anatolia still borders Muslim Mesopotamia and Iran, it's not exactly super safe. Preventing Manzikert is just one step, you need more stuff down the line.
Also it could be possible in the early modern period, if the empire survives the Mongol invasions. It could extend into the Levant, Mesopotamia and Egypt. The Ottoman Empire managed to achieve this in OTL, why can't the Byzantines. The spread of the Byzantine Empire into Egypt would make the Spanish and Portuguese more likely to conqueror areas of North Africa.