Place shrimp on a work surface. Slice each shrimp horizontally through the middle, being careful not to cut all the way through to the other side. Open the 2 sides and spread them out like butterfly wings.
Mix 2 tablespoons oil, minced garlic, salt, red pepper flakes, and cayenne pepper together in a bowl. Toss shrimp into the oil marinade and set aside.
Heat remaining 2 tablespoons oil in a pan over low heat. Add sliced garlic. Cook until golden and infused in the oil, about 2 minutes. Remove garlic. Increase heat to medium. Add shrimp and marinade; cook until shrimp is pink, about 5 minutes. Remove shrimp from pan.
Add onion, yellow bell pepper, and jalapeno to the pan; cook and stir until tender, about 10 minutes. Add diced tomatoes, 1/2 the parsley, 1/2 the basil, oregano, and black pepper. Cook until reduced to your desired thickness, 15 to 20 minutes.
Meanwhile, bring a large pot of lightly salted water to a boil. Cook spaghetti in the boiling water, stirring occasionally, until tender yet firm to the bite, about 12 minutes. Drain.
Toss spaghetti noodles into the tomato-pepper sauce and stir in shrimp. Sprinkle remaining parsley and basil on top. Serve immediately.