The color of the pot could be a factor if it is dark. If it's ~95ยฐ, like I'm sure it is every day for months in Austin, and the sun is shining on a dark pot, the roots could reach much higher temps than ambient. If the surface of the pot is too hot to comfortably put your hand there, plant roots feel the same way. Some desert plants might take that in stride, but most leafy plants do not, IME with pots. I've given up trying to have any leafy plants in pots if they require a lot of sun. Just too hot while the same plants directly adjacent but in the ground will be happy, and pots in the sun need water every day, too much work.
...but it looks like this grow site is under a big oak tree. If grass won't grow, it's not enough sun for pepper plants. I agree with the suggestion to claim some of the grassy area for a veg patch. Just north of a big tree has been my best exposure for veg patch, offering a bit of relief during the middle of the day.
Right after a rain, the soil should be easier to dig. If you want to be lazy about it, smother a spot now with a thick layer of organic matter and use it next spring. Or get a baby pool, poke a bunch of holes in it, and use that as a giant pot or small plot. Or get some white 5-gallon buckets and add drain holes. Trash cans can also be great pots, with holes added, and the same size vs. a pot is almost always a LOT less expensive.
Those look like tiny pots for something like a pepper plant. If you weren't watering daily during the heat, I'm not surprised pepper plants didn't do well. Unless it rained really hard, not much moisture would fall under the tree canopy.
I think you'll have much better results if you get soil labeled palm/cactus, vs. potting soil. Any potting soil I've seen is usually just peat with a few bits of perlite. Nothing will grow for me in that. BUT the palm/cactus soil is so chunky that it dries in about 10 mins. If you mix that by about half with some ground dirt, you should end up with decent plants that don't rot but don't need to be watered every day.
