eugyppius

... and to the dynastic disputes that distracted the government after Heraclius's death. They also report that Egyptians did not welcome Arab rule and were in fact terrified of it. For what it's worth.

John of Nikiu, one near-contemporary chronicler, sees the Arab conquest as a judgment of God upon Heraclius for persecuting the orthodox Monophysites. A very typical ancient-world attitude.

In the long-run, however, it's true that Monophysites persist under Arab rule in Syria. In Asia Minor, which remains under eastern Roman control, they are gradually eliminated by relentless Chalcedonian imperial pressure.

If you were a Monophyist, Arab rule probably was a better deal, at least doctrinally/theologically.

In closing, I'd propose another way to look at this. The Monophysite position just seems more natural and intuitive to me, and was perhaps the old way of viewing the nature of the Word.

The 2-nature orthodoxy promulgated Chalcedon – at least in those precise terms, put that starkly – was perhaps the true innovation. This would explain Chalcedonianism works primarily in the theologically unsophisticated western Empire (popes at Rome are not big theologians)...

... and in Constantinople, where the emperor be at. In the Eastern provinces, they go on believing as they always had. The archaic theologies remain at the fringes, far from power.

Other early heresies, like the Donatists, also seem to work like this. The 'orthodox' position is the innovation or compromise, the 'heretics' are the older beliefs to be replaced.