In a saucepan, cover 4 of the eggs with 1 inch of cold water and bring to a boil over medium-high heat for 6 minutes.
Transfer to a bowl of ice water. Peel, then set aside.
Meanwhile, in a frying pan, saut the onion and bell peppers in olive oil over medium heat until softened.
Add the garlic and cook for 1 to 2 minutes more, then let cool.
Beat the remaining two eggs in a large mixing bowl. Add the milk, Parmesan, breadcrumbs, herbs, and salt and pepper.
Add the meats and half of the onion/pepper mixture. Gently combine with your hands, being careful not to over-mix.
With a rolling pin, roll the meat out into an 8- by 5-inch rectangle between sheets of wax paper. Distribute the remaining onion/pepper mixture lengthwise down the center of the meat.
Lay 3 to 4 of the hard-cooked eggs end to end on top of the onion/pepper mixture. Bring the sides of the meat rectangle up over the eggs and vegetables and pinch all the seams closed. Put seam-side down on a rimmed baking sheet or in a loaf pan.
When ready to cook, start the Traeger grill on Smoke with the lid open until the fire is established (4 to 5 minutes).
Set the temperature to 350F and preheat, lid closed, for 10 to 15 minutes.
Bake the meatloaf for about 1 hour, or until an instant-read meat thermometer inserted in the middle of the loaf reads 165F.
If desired, pour the marinara sauce over the top of the Meatloaf and bake for 10 to 15 minutes more. Let cool slightly before slicing and serving. This is also excellent when served cold.