Preheat your air fryer to 400°F (200°C).
Slice the russet potato into even wedges, toss with the avocado oil, and season with a pinch of sea salt.
Place the potato wedges in the air fryer basket and cook for 15-18 minutes, shaking halfway through, until they are crispy and tender.
While the potatoes cook, whisk together the flour, light beer, garlic powder, paprika, sea salt, and black pepper in a shallow bowl until a smooth, thick batter forms.
Pat the cod fillets completely dry with a paper towel and then dip each piece into the batter, ensuring it is fully and evenly coated.
Lightly grease the air fryer rack, place the battered fish inside, and air fry at 375°F (190°C) for 10-12 minutes until the coating is golden and the fish flakes easily.
Serve the hot fish and chips immediately with a fresh lemon wedge for a bright finish.