Heat the oil in a large Dutch oven over medium-high heat until shimmering. Add the carrots, celery, onion, and zucchini; cook until softened, about 5-7 minutes. Add the garlic and cook, stirring, until fragrant, about 30 seconds.
Stir in the green beans, thyme, bay leaf, and broth. Bring to a boil, then reduce the heat and gently simmer the soup, uncovered, until the vegetables are tender, about 10-15 minutes.
Stir in the noodles and frozen peas; cook the noodles according to the package directions for just barely al dente, about 5-7 minutes. Remove the pot from the heat; stir in the parsley and lemon juice. Season with salt and pepper, to taste.
Ladle the soup into individual serving bowls. Garnish with additional fresh herbs, if desired.