Preheat the smoker. Set your smoker to 250°F (120°C) and use wood chips like hickory, mesquite, or applewood for a deep, smoky flavor.
Cook the bacon. In a large skillet, cook the diced bacon over medium heat until it’s crispy. Remove the bacon with a slotted spoon and set aside, leaving about 2 tablespoons of bacon fat in the pan.
Sauté the vegetables. Add the diced green and red bell peppers, onion, and garlic in the same skillet with the bacon fat. Sauté for 5-7 minutes until the vegetables are soft and starting to caramelize.
Mix the beans and sauce. In a large bowl (or baking pan), combine the pork and beans, sautéed vegetables and bacon, ketchup, BBQ sauce, brown sugar, apple cider vinegar, Worcestershire sauce, Dijon mustard, smoked paprika, chili powder, cumin, black pepper, and cayenne pepper (if using). Stir until everything is well combined.
Transfer to a pan. Pour the bean mixture into a large cast iron skillet, Dutch oven, or aluminum baking pan that is safe for the smoker. Spread the mixture evenly.
Smoke the beans. Place the pan in the smoker and smoke uncovered for 2.5 to 3 hours, stirring halfway through. The beans should thicken and noticeably darken.
Finish and serve. Once the beans are thick and bubbling, carefully remove them from the smoker. Let them rest for 10-15 minutes to cool slightly before serving.