46+ Brown Spots On Pepper Plant Leaves. I think this sounds like aphids. They are tiny white bugs, usually found on the back of plant leaves.
Bacterial leaf spot comes to mind but i;ve never actually seen it and the pictures i can find online look somewhat different.
Pepper plants with brown or burnt thinning skin usually comes from your soil not being covered with mulch. As these get bigger they spread to larger parts of the leaf and the center of the lesion becomes brown and dried, eventually breaking out entirely and. To prevent the spread of this disease, avoid overhead watering and remove. Brown leaves often mean that your plant is under watered.