Heat olive oil in a large skillet over medium heat.
Add diced onion and sliced red bell pepper; cook for 3 to 4 minutes until softened.
Stir in minced garlic, smoked paprika, and chili flakes; cook for 30 seconds.
Add rice and cook for 1 minute, stirring to coat the grains.
Pour in broth, saffron or turmeric, crushed tomatoes, salt, and pepper; bring to a boil.
Reduce heat and simmer uncovered for 12 to 15 minutes without stirring.
Arrange shrimp, mussels, calamari, and crab on top of the rice.
Cover the skillet and cook for 5 to 7 minutes until seafood is cooked and rice is tender.
Scatter frozen peas over the dish; drizzle with lemon juice and sprinkle chopped parsley.
Serve directly from the skillet with lemon wedges on the side.