Bring chicken stock to a boil in a pot over medium-high heat; slowly whisk in grits to prevent clumping.
Reduce heat to medium-low and cook grits until tender, about 5 minutes.
In a large skillet, cook diced bacon until crispy; transfer to paper towels and reserve half the bacon grease.
Add butter, cream cheese, heavy cream, and shredded cheeses to the cooked grits; stir until smooth and cheese is melted.
Season grits with seasoned salt and pepper; add additional cream or stock if needed to adjust consistency; keep warm.
Toss shrimp with olive oil and coat evenly with Cajun seasoning, reserving 1/2 teaspoon for sauce.
Cook shrimp in reserved bacon fat over medium-high heat, flipping once until shrimp are opaque, about 4 minutes; remove and tent with foil.
In the same skillet, melt butter and sauté garlic and scallions until fragrant, about 2 minutes.
Add reserved Cajun seasoning, red pepper flakes, Calabrian peppers with oil; cook for 1 more minute.
Pour in chicken stock, scraping up browned bits; add lemon juice, Worcestershire sauce, and heavy cream; whisk to combine into a sauce.
Return shrimp to the pan with the sauce, add parsley, toss to coat, and add an extra dash of lemon juice.
Serve by spooning creamy grits into bowls, topping with shrimp and pan sauce, and finishing with crispy bacon.