Heat the butter and oil in a large pot or Dutch oven over medium-high heat. Once the butter has melted, add the onion, celery, and garlic, and cook, stirring often, until the onion is translucent and the garlic is fragrant, 2 to 3 minutes.
Sprinkle in the flour and stir to combine thoroughly. Continue to cook 1 to 2 more minutes.
Season with the lemon zest, salt, pepper, and chili flakes, continuing to stir. Slowly whisk in the broth and milk, ensure there are no clumps. Add the marinated artichoke hearts and noodles. Increase the heat to high and bring to a simmer. Once at a simmer, reduce the heat to low, cover and cook until the noodles are al dente, 12 to 15 minutes.
Remove the lid and stir in the mozzarella, parmesan, and cream cheese. Continue to stir until melted throughout. Right before serving, mix in the fresh lemon juice spinach over low heat, stirring until the spinach is just wilted. Taste and adjust seasonings if necessary.
Serve immediately with more red pepper flakes, a sprinkle of vegan parmesan, and some fresh minced parsley, and enjoy!