WI emperor of the Romans Constantine IV survives

So WI Constantine IV does not die. How would this affect Byzantine history. Constantine was a brilliant byzantine emperor. He died at 33 and Justinian II became emperor. So if Constantine ruled for another 3-4 decades how would Byzantine history be changed
 
All of Justinian's accomplishments and then some, with any reasonable stroke of fortune.

But 4 decades would be a long time. 3 is more likely.
 
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