What religion where the Egyptians who oppressed the Israelites?
The Egyptian religion consisted of dozens of gods—they were very wealthy, and had a wealthy priesthood, also. Since the Egyptian culture was so old, some of their gods were thousands of years old at the time of Israelites. The Israelites were very poor, they couldn’t afford more than one god, so they made the most of the one that they had.
No Egyptians ever oppressed the Israelites. The myth that the Israelites were slaves in Egypt and saved by Moses isn’t supported in any way by the historical or archeological evidence. At any rate, Egyptian religion is quite varied, and changed from time to time. Mainly polytheistic, though one dynasty did attempt to impose a strange sort of monotheism for a short time — it was abandoned when that dynasty went out of power. Peace.