Complex sentence: The Monophysites living in Egypt, unhappy with Chalcedonian orthodoxy, were not eager to aid Byzantine imperial forces and afterward were supported by Khosrau, but neither did they resist imperial forces between 600 and 638 and many saw the Persian occupation in negative terms.
Split into simpler sentences: The Monophysites living in Egypt were unhappy with Chalcedonian orthodoxy and were not eager to aid Byzantine imperial forces. Afterward they were supported by Khosrau, but they did not resist imperial forces between 600 and 638, and many saw the Persian occupation in negative terms.