Preheat your air fryer to 400°F (200°C).
Scrub the potato and cut it into thin, even wedges; toss them in a bowl with the olive oil and half of the sea salt and black pepper.
Place the potato wedges in the air fryer basket in a single layer and cook for 15-18 minutes, shaking halfway through, until they are golden and crispy.
While the potatoes cook, whisk together the flour, light beer, garlic powder, paprika, and the remaining salt and pepper in a shallow bowl until the batter is smooth.
Pat the cod fillets thoroughly dry with paper towels and slice them into 3-4 large strips.
Dip each fish strip into the beer batter, allowing any excess to drip off, and place them carefully into the air fryer basket once the potatoes are done (keep potatoes warm in a low oven).
Air fry the fish at 375°F (190°C) for 10-12 minutes, flipping gently halfway through, until the coating is set and the fish flakes easily with a fork.
Serve the hot fish alongside the golden fries with a fresh lemon wedge for squeezing.