ames, I’ll answer to the best of my knowledge.
True evil can only come from bechirah, i.e. choosing to do evil. You are correct that shaidim and mazikim were created to do destructive things and that it is Hashem’s will that they fulfill this tafkid. But are their jobs not to perform acts of evil? They are not punishable for it, because that is their tafkid and they have no ability to do otherwise. But if a person did those acts they would be punished for it.
Hashem created darkness. The choshech mitzraim was not merely the absence of light. It was a briah.
Hashem created evil. He also bestowed upon man the ability to choose. But what choices would be available to man if He had not created evil? We would have no bechira if only good existed.
This is an esoteric concept, and I hope that you ask it to someone more qualified than me.