Preheat your air fryer to 400°F (200°C).
Slice the russet potato into even wedges, then toss them in a bowl with the olive oil and half of the sea salt and black pepper.
Arrange the potato wedges in a single layer in the air fryer basket and cook for 15-18 minutes, shaking halfway through, until they are browned and tender.
While the potatoes cook, pat the cod fillets completely dry with paper towels and cut them into large strips.
In a medium mixing bowl, whisk together the flour, garlic powder, paprika, and the remaining sea salt and black pepper.
Slowly pour the cold light beer into the flour mixture, whisking gently until a smooth, thick batter forms.
Dip each cod strip into the batter to coat thoroughly, allowing any excess to drip off before placing them onto a parchment-lined plate.
Once the potatoes are done, remove them and keep warm; then lightly grease the air fryer basket with a small amount of oil.
Place the battered fish in the basket without crowding and air fry at 375°F (190°C) for 10-12 minutes, flipping carefully halfway through, until the exterior is crunchy and golden.
Garnish the fish and chips with finely chopped fresh parsley and serve immediately while hot.