Heat oil in a large deep pot or Dutch oven over medium; sauté garlic 1 minute until fragrant.
Add cherry tomatoes, sun-dried tomatoes, and olives; cook 3-4 minutes until cherry tomatoes start softening.
Add broth, oregano, pepper flakes, salt, and black pepper; bring to a boil.
Submerge penne, stirring; reduce heat to medium and cook 12-15 minutes, stirring occasionally, until al dente and most liquid absorbed.
Add spinach; cook 1-2 minutes until wilted.
Off heat, top with feta and fresh basil; serve immediately.