In a medium pot, heat 2 teaspoons oil over medium. Add onion and cook until softened, 8 minutes; season with salt and pepper. Add garlic, cumin, and cinnamon and cook until fragrant, 30 seconds. Transfer mixture to a medium bowl and add beef. Using your hands, gently combine (do not overmix), then form beef mixture into 1-inch balls.
Add remaining 2 teaspoons oil to pot and heat over medium-high. Add sweet potatoes and carrots and cook until bright orange, 5 minutes. Add tomato paste and stir to coat. Add broth and bring to a simmer; cook until vegetables are just tender, about 5 minutes. Add meatballs and simmer until cooked through, 12 minutes. Sprinkle with cilantro to serve.