I am a newb gardener so I may be waaaay off base but they look like they are sun burned.

It seems that you have a mixed batch. I see one chewed and eaten by some thing. I see some with environmental damage( cold,bite, hail ?,..) I see one that looks just fine.

All in all, peppers are less tolerant to cold than say tomatoes. So then once the weather and soil warm up, they should start moving. I just have couple of pepper plants, that I planted at the same time that I planted some tomato plants. In comparison, the peppers are just hanging in there but are healthy. Another thing that I have noticed , some peppers have light green color, as if they have some deficiency. But that is not the case.

Dying, I think, is due to root rot. And that in turn could be due to excess rain, water. This has happened to my basils.

Pull back the mulch and grow your peppers on bare gound until they really start growing. This helps the soil warm up, speeds drying of the leaves, and does not set up habitat for slugs and chewing insects. When it gets hot and the plants are more than a foot tall, mulch them and them mulch some more.

Your container pepper looks like it's in a pretty big pot. If you start small and move them to bigger pots gradually, they grow really fast.

Thanks all so no is thinking disease or fungus, based on the last three seasons my confidence is low but I'll go back and buy a few more now that the weather is warmer. As far as compost it's mostly tree leaves and grass clippings with some kitchen scraps, the container fertilizer was in a pretty low dosage.