Preheat the oven to 400°F (200°C) and line a baking sheet with parchment paper. Arrange biscuit halves cut-side up.
Cook the garlic in melted butter over medium heat in a skillet for about 60 seconds until fragrant.
Add shrimp and cook for 2 to 3 minutes until pink and opaque. Remove from heat immediately.
Mix the filling by combining cooked shrimp, crab meat, cream cheese, mayonnaise, Old Bay, smoked paprika, lemon juice, and green onions in a bowl. Stir gently.
Load the biscuits by spooning the seafood mixture evenly over each biscuit half and pressing lightly.
Top with cheese and bake for 8 to 10 minutes until melted and bubbling.
Broil for 1 to 2 minutes for a golden cheese top. Watch closely to avoid burning.
Serve immediately garnished with extra green onions or a squeeze of fresh lemon.