Bring a large pot of salted water to a boil. Trim ends from zucchini. Shave zucchini lengthwise into thin ribbons; discard core. Peel and finely chop garlic.
Cook pasta until al dente, then drain.
Heat drizzle of oil in a large pan over medium-high heat. Add garlic and cook until fragrant. Add beef, Italian seasoning, salt, and pepper. Cook until meat is browned and cooked through.
Add tomato paste and cook until fully incorporated. Stir in water and stock concentrate. Bring to a boil and cook until thickened.
Stir in cream cheese until melted, then add zucchini ribbons, pasta, and butter. Toss until thoroughly combined, zucchini ribbons are tender and pasta is coated in a creamy sauce. Turn off heat. Taste and season as necessary.