I don't see any insect damage on your plants. Can you post a photo of that? Or even better, the insect you call "amphids" (nothing by that name is on Google)? The fly you show could be one of many beneficial insects that will eat your amphids. I dont know of any flies that attack pepper plants. It's advisable to identify the pest you want to eliminate before you choose the pesticide you use. You can actually cause more damage to your plant with pesticides than pests might cause.

I'm guessing that's a hover fly (a good guy). They eat aphids.

Here is a link that might be useful: Hover flies eat aphids