I mean, I've already made a
thread that would include this question, but sure, I'll bite.
Religious minorities were getting persecuted by the Romans up until the Arab invasions. Assuming many of the copts and nestorians still go along with the arabs but are defeated, it could get better or worse for them.
On the one, hand the Romans would want to reconcile, and eventually they would have to start treating them better with a hostile Arab world next to them. But on the other hand, many of them DID just revolt. The most likely outcome is many are executed/moved around, and over the decades the Romans start treating them better.
Now as for the Arabs reinvading, of course they might. Assuming they managed to still take much of Persia, they will have a huge resource base to work with. I could see the region falling, or even changing hands multiple times in the next couple of centuries.