Bring a large pot of lightly salted water to a boil. Cook spaghetti in the boiling water, stirring occasionally, until tender yet firm to the bite, about 12 minutes. Drain.

Place bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned, about 10 minutes. Drain bacon slices on paper towels. Crumble into small pieces.

Whisk eggs, milk, salt, and pepper together in a bowl.

Heat avocado oil in a large skillet over medium heat. Add spaghetti, milk mixture, peas, and garlic; cook and stir until milk mixture is heated through and coats the spaghetti, 5 to 10 minutes. Stir in bacon and Parmesan cheese. Garnish with parsley.