Heat olive oil in a large paella pan or wide skillet over medium heat.
Add the chopped onion and diced red bell pepper, and sauté for 5 minutes until softened.
Add the minced garlic and cook for 1 minute until fragrant.
Stir in the Arborio rice, smoked paprika, saffron threads, salt, black pepper, and cayenne pepper. Cook for 2 minutes, stirring frequently to coat the rice with the oil and spices.
Pour in the chicken broth, seafood stock, and drained diced tomatoes. Stir to combine and bring to a simmer.
Reduce heat to medium-low and cook uncovered for 15 minutes without stirring, allowing the rice to absorb the liquid.
Arrange the shrimp, mussels, clams, and squid rings evenly over the rice. Sprinkle frozen peas on top.
Cover the pan with a lid or aluminum foil and cook for an additional 10-15 minutes until the seafood is cooked through and the rice is tender.
Remove from heat and let the paella rest covered for 5 minutes.
Garnish with chopped fresh parsley and serve with lemon wedges on the side.