Dice three-quarters of the onion and finely chop garlic. Clean and wash red pepper. Pat pork schnitzel dry. Slice pepper and meat into thin strips.
Mix 4 tablespoons oil, 1 teaspoon paprika, pepper, and oregano. Combine meat with marinade. Cover and refrigerate for 30 minutes.
Slice cabbage into fine strips. Dice remaining onion. Heat 1 tablespoon oil in a large pan over medium heat. Sauté onion for 3-4 minutes until translucent. Add cabbage, roughly 125 ml water, and broth. Cover and braise for 10-15 minutes. Season with salt and pepper.
Heat a large pan over medium-high heat. Fry gyros in batches until pork reaches 63°C/145°F internal temperature. Season with salt and set aside. Sprinkle flour into the remaining fat and stir for 1-2 minutes. Stir in milk, bring to a boil, then simmer for 5 minutes. Return gyros to the pan.
Grate feta cheese. Stir crème fraîche and half the feta into the sauce. Season with pepper and salt to taste.
Layer cabbage and gyros sauce alternately in a greased baking dish. Sprinkle remaining feta on top. Bake in a preheated oven at 200°C/392°F (or 175°C/347°F for fan oven) for 25 minutes.