Last year I grew grocery-store size bell peppers for the first time ever. I grew them in Earthboxes. I don’t know if it was the continuous soil moisture (no water stress, ever) or the way the fertilization is set up. But since it worked, I’m planting peppers in Earthboxes again this year.
When I have done peppers in the ground, my results were like yours: small, thin-walled, not many, and not very tasty. Maybe it was nematodes (definitely have those), a nutrition issue, or water stress.
Moisture is a good point. I have some peppers indoors. The one that is doing best has a continuous supply of moisture using a plastic soda bottle using a special top and ceramic gizmo to slowly water the plant as needed.
I grow tomatoes and peppers in Earth Boxes, and ALWAYS get great results. I have some unusual/hard to find tomatoes that I would NEVER risk in the crap soil of Red Hampshire. I have also had good results growing bell peppers in 3-gallon pots...you can move them inside in case you get a frosty night before they have finished turning color. Watering from below is key.
I’m ordering some earthgrow pots, for my sweet peppers. My hot peppers do fine in my raised gardens.