Place peeled and cubed potatoes in a large pot filled with cold salted water and bring to a boil. Simmer until fork-tender, about 12-15 minutes.
Pat shrimp dry with paper towels, then season with paprika, garlic powder, salt, and black pepper.
Heat olive oil in a large skillet over medium-high heat. Add shrimp in a single layer and sear about 2 minutes per side until pink and golden. Remove and set aside.
In the same skillet, reduce heat to medium and melt 2 tablespoons butter. Add minced garlic and sauté until fragrant, about 30-45 seconds.
Pour in heavy cream and broth, whisk to combine, and simmer gently. Gradually stir in grated Parmesan until melted and sauce thickens, about 3-4 minutes.
Add nutmeg and cracked black pepper to taste. Adjust seasoning with salt if needed.
Drain potatoes thoroughly and return to the hot pot. Add butter and cream, mash until smooth and creamy, seasoning with salt and white pepper as desired.
Return shrimp to the garlic cream sauce and cook for an additional 2-3 minutes until shrimp are fully cooked and coated in sauce.
Serve shrimp atop a bed of mashed potatoes, garnish with fresh thyme, red chili flakes, parsley, and extra Parmesan as desired.