Preheat the smoker to 250°F. Add the cherry wood chips or chunks according to the smoker’s directions. Line a rimmed tray with foil or use a smoker-safe tray.
In a large bowl, combine the pork, panko, egg, grated onion, grated apple, Dijon mustard, maple syrup, 1 teaspoon kosher salt, smoked paprika, and black pepper. Mix gently until everything is evenly distributed, taking care not to pack the mixture tightly.
Divide the mixture into four portions and shape each into a small loaf. Set them on the prepared tray with space between them. Smoke until the centers reach 160°F on an instant-read thermometer, about 1 to 1 1/2 hours depending on their shape and the smoker.
While the meatloaves smoke, put the sweet potato chunks in a saucepan and cover them with water. Bring to a boil, then simmer until they are very tender when pierced with a fork, about 15 to 20 minutes. Drain well.
Mash the sweet potatoes with the butter, warmed milk, and 1/4 teaspoon kosher salt until smooth. Add the milk gradually so the mash stays thick and creamy.
Let the meatloaves rest for 5 minutes after removing them from the smoker. Spoon sweet potato mash onto four plates and serve one meatloaf with each portion.